Method and system for preventing wafer flying and semiconductor equipment

Abstract

The invention provides a method and system for preventing wafer flying and a semiconductor device, and the method comprises the following steps: selecting a plurality of measurement points at different positions on the surface of a wafer, and obtaining the radiance value of each measurement point in real time below the wafer in the technological process, and calculating a radiance uniformity value according to the radiance value of each measurement point, comparing the radiance uniformity value with a preset critical threshold, and giving an alarm when the radiance uniformity value is greater than the preset critical threshold. According to the method, the radiance value is measured at multiple points, the radiance at different positions of the wafer is measured in the technological process, the radiance uniformity value is calculated, the deformation quantity of the wafer can be indirectly represented, the measurement of the radiance is not influenced by the temperature of the wafer, the measured value is accurate and reliable, and the measurement precision is high. Therefore, the wafer flying accident caused by excessive deformation of the wafer can be effectively prevented.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor manufacturing technology, and more specifically relates to a method, system and semiconductor equipment for preventing wafer flying. Background Art

[0002] In integrated circuits, RTP (rapid thermal processing) equipment is used as a device for growing gate oxide films. Its principle is to use a thermal oxidation process to grow a uniform ultra-thin silicon dioxide film on the surface of a single wafer. The equipment needs to use a magnetic suspension motor to drive the wafer to rotate at high speed during the heating process to achieve better film uniformity. During the high-speed rotation process, if the wafer is deformed due to uneven heating, it will cause the wafer to fly out of the rotating mechanism, resulting in serious consequences such as wafer breakage. Therefore, a reliable early warning mechanism is needed to warn of the wafer flying out. At present, the early warning scheme adopted by existing equipment is to monitor the temperature difference between various areas of the wafer through a temperature probe, and issue an early warning when the temperature difference is greater than the set threshold. However, when the wafer temperature is lower than 400°C, the sensitivity and accuracy of this temperature probe are seriously affected and cannot accurately reflect the actual temperature of the wafer. Therefore, relying on temperature difference for flying wafer early warning is not reliable, and often results in false alarms or untimely alarms. Summary of the invention

[0003] Based on the technical problems existing in the prior art, the present invention provides a method, system and semiconductor equipment for preventing wafer flying, aiming to solve the technical problems in the prior art that the existing equipment monitors the temperature difference between various areas through temperature probes, and relying on temperature differences for wafer flying warning is unreliable and often causes false alarms or untimely alarms.

[0004] To achieve the above objectives, in a first aspect, an embodiment of the present invention provides a method for preventing wafer flying, comprising the following steps: Step 1. Select multiple measurement points at different positions on the wafer surface; Step 2. During the process, the emissivity value of each measuring point under the wafer is obtained in real time; Step 3. Calculate the emissivity uniformity value based on the emissivity value of each measuring point; Step 4: Compare the radiation uniformity value with a preset critical threshold value. When the radiation uniformity value is greater than the preset critical threshold value, an alarm is issued.

[0005] Optionally, the emissivity uniformity value is calculated using the following formula: emissivity uniformity value=(maximum emissivity value−minimum emissivity value) / average value of each emissivity.

[0006] Optionally, the number of measurement points is two.

[0007] Optionally, the two measurement points are located in a central area of ​​the wafer and an edge area of ​​the wafer respectively.

[0008] Optionally, the number of measurement points is three.

[0009] Optionally, the three measurement points are respectively located at a central area of ​​the wafer, a quarter of the diameter of the wafer, and an edge area of ​​the wafer.

[0010] Optionally, step 1 includes: arranging a plurality of radiation rate probes at intervals below the wafer, and arranging the radiation rate probes at intervals from each other.

[0011] In the second aspect, an embodiment of the present invention provides a system for preventing wafer flying, including multiple radiometric probes and a controller. The radiometric probes are used to collect the radiometric values ​​of measurement points on the wafer. The controller is used to calculate the radiometric uniformity value based on the radiometric values ​​of the measurement points, and determine whether the radiometric uniformity value is greater than a preset critical threshold. When the radiometric uniformity value is greater than the preset critical threshold, the controller issues an alarm and stops the process.

[0012] Optionally, the controller includes: a uniformity calculation module, which is used to calculate the radiation uniformity value based on the radiation value of the measuring point; a judgment and analysis module, which compares the radiation uniformity value with a preset critical threshold to determine whether the radiation uniformity value is greater than the preset critical threshold; and an alarm module, which issues an alarm when the radiation uniformity value is greater than the preset critical threshold.

[0013] In a third aspect, an embodiment of the present invention provides a semiconductor device, including a system for preventing wafer flying as described in any one of the second aspects above.

[0014] Compared with the prior art, the embodiments of the present invention have the following beneficial effects: A method for preventing wafer flying of the present invention selects a plurality of measuring points located at different positions on the surface of the wafer, obtains the emissivity value of each measuring point in the process in real time, calculates the emissivity uniformity value according to the emissivity value of each measuring point, compares the emissivity uniformity value with a preset critical threshold value, and issues an alarm when the emissivity uniformity value is greater than the preset critical threshold value. During the process, the wafer often undergoes a certain deformation due to high temperature, causing the measured value of the emissivity to deviate from the actual emissivity value of the wafer, and the value of the deviation is related to the deformation amount of the wafer, so the present invention adopts multi-point measurement of the emissivity value, and measures the emissivity at different positions of the wafer during the process and calculates the emissivity uniformity value, which can indirectly characterize the deformation amount of the wafer, and the measurement of the emissivity will not be affected by the temperature of the wafer, and the measured value is accurate and reliable, thereby effectively preventing the flying accident caused by excessive deformation of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0016] Figure 1 A flowchart of a method for preventing wafer flying provided by an embodiment of the present invention; Figure 2 A schematic diagram of the distribution of measurement points on a wafer provided by an embodiment of the present invention; Figure 3 A semiconductor device is provided in an embodiment of the present invention.

[0017] The reference numerals in the above drawings are as follows: 1. Wafer; 2. Measurement point; 3. Radiation rate probe; 4. Controller; 5. Process chamber; 6. Light box; 7. Edge ring; 8. Support ring; 9. Halogen lamp. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by 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.

[0019] It should be noted that when an element is referred to as being "fixed to" or "arranged on" another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element. In the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0020] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0022] As described in the background technology, the warning scheme currently used by existing equipment is to monitor the temperature difference between various areas of the wafer through a temperature probe, and issue a warning when the temperature difference is greater than the set threshold. However, when the wafer temperature is lower than 400°C, the sensitivity and accuracy of this temperature probe are seriously affected and cannot accurately reflect the actual temperature of the wafer. Therefore, relying on temperature difference for wafer flying warning is not reliable, and often results in false alarms or untimely alarms.

[0023] The present invention provides a method for preventing wafer flying. During the heating process performed by RTP equipment, the emissivity at different positions of the wafer is measured and the emissivity uniformity value is calculated to characterize the deformation of the wafer, thereby effectively preventing wafer flying accidents caused by excessive deformation of the wafer.

[0024] It should be noted that the measured value of the emissivity is not only related to the actual emissivity of the wafer (fixed value), but also to the distance between the wafer and the measuring instrument. During the heating process of the RTP equipment, the wafer will deform to a certain extent due to the high temperature, causing the distance between the wafer and the measuring instrument to change, resulting in the measured value of the emissivity deviating from the actual emissivity of the wafer, and the deviation value is related to the deformation of the wafer.

[0025] See also Figures 1 to 3 As shown, the first aspect of the present invention provides a method for preventing wafer flying, comprising the following steps: Step 1. Select multiple measuring points 2 located at different positions on the surface of the wafer 1, wherein the multiple measuring points 2 are preferably located on different circumferences of the wafer 1, such as Figure 2 shown.

[0026] See also Figure 3 As shown, in some embodiments of the present invention, the subject that performs the radiation rate measurement is the radiation rate probe 3. The number of the measurement points 2 is two or more.

[0027] See also Figure 3 As shown, in some embodiments of the present invention, step S1 includes: arranging a plurality of radiation rate probes 3 at intervals below the wafer 1 , and arranging the radiation rate probes 3 at intervals from each other.

[0028] In some embodiments of the present invention, there are two measuring points 2. For example, two measuring points 2 are set at different positions on the surface of the wafer 1 in this embodiment, and the two measuring points 2 cannot be on the same circumference.

[0029] In some embodiments of the present invention, two measuring points 2 are respectively located in the center area of ​​wafer 1 and the edge area of ​​wafer 1. During the process, the emissivity value of the center area of ​​wafer 1 usually changes the most, and the emissivity value of the edge area of ​​wafer 1 changes the least. The emissivity value of the measuring point 2 located in the center area of ​​wafer 1 is used to characterize the deformation amount of the maximum deformation area (center area) of wafer 1 during the process, and the emissivity value of the measuring point 2 located in the edge area of ​​wafer 1 is used to characterize the deformation amount of the minimum deformation area (edge ​​area) of wafer during the process as a reference value. By selecting two measuring points 2 located in the center area and the edge area of ​​wafer 1, it is possible to quickly know whether the deformation of wafer 1 exceeds the preset range, so as to give an alarm in time to prevent the occurrence of flying wafer accidents.

[0030] See also Figure 2 As shown, in some other embodiments of the present invention, the number of measuring points 2 is three. By measuring multiple measuring points 2, multiple emissivity values ​​are obtained, thereby improving the reliability of flying chip warning.

[0031] In other embodiments of the present invention, the three measuring points 2 are respectively located in the central area of ​​the wafer 1, at one quarter of the diameter of the wafer 1, and at the edge area of ​​the wafer 1. During the process, the emissivity value of the measuring point 2 located in the central area of ​​the wafer 1 is used to characterize the deformation amount of the maximum deformation area (central area) of the wafer 1 during the process, the emissivity value of the measuring point 2 located in the edge area of ​​the wafer 1 is used to characterize the deformation amount of the minimum deformation area (edge ​​area) of the wafer during the process as a control value, and the emissivity value of the measuring point 2 located at one quarter of the diameter of the wafer 1 (between the central area and the edge area) is used as a reference value of the deformation amount.

[0032] Step 2. During the process, the emissivity value of each measuring point 2 is obtained in real time below the wafer 1; See also Figure 3 As shown, in an embodiment of the present invention, the emissivity probe 3 is arranged toward the back side of the wafer 1 , and the emissivity probe 3 can emit infrared light to the wafer 1 and receive the infrared light reflected by the wafer 1 .

[0033] Step 3. Calculate the emissivity uniformity value according to the emissivity value of each measuring point 2; In an embodiment of the present invention, the emissivity uniformity value calculation formula is as follows: Emissivity uniformity value = (maximum emissivity - minimum emissivity) / average value of each emissivity.

[0034] For example, Figure 2 As shown, A, B, and C are divided into three measurement points 2 located in the edge area, the 1 / 4 diameter area, and the center area of ​​the wafer 1. Three radiation rate probes 3 are used to measure the three points A, B, and C respectively and perform uniformity calculation: Assume that the emissivity values ​​measured by the three emissivity probes 3 are E A 、E B 、E C , the radiance uniformity value is calculated as follows:

[0035] Step 4: Compare the radiation uniformity value with a preset critical threshold value. When the radiation uniformity value is greater than the preset critical threshold value, an alarm is issued.

[0036] It is understandable that when the calculated emissivity uniformity value is greater than the preset critical threshold, it means that the wafer 1 is in a state of large deformation due to uneven heating and the like. At this time, an alarm is issued and the process is stopped to prevent the wafer 1 from flying.

[0037] The above technical solution provided by the embodiment of the present invention is applied, by selecting multiple measuring points 2 located at different positions on the surface of the wafer 1, the emissivity value of each measuring point 2 during the process is obtained in real time, and the emissivity uniformity value is calculated according to the emissivity value of each measuring point 2, and the emissivity uniformity value is compared with the preset critical threshold value. When the emissivity uniformity value is greater than the preset critical threshold value, an alarm is issued. During the process, the wafer 1 often undergoes a certain deformation due to high temperature, resulting in the measured value of the emissivity deviating from the actual emissivity value of the wafer 1, and the deviation value is related to the deformation of the wafer 1. Therefore, the present invention adopts multi-point measurement of the emissivity value, and by measuring the emissivity at different positions of the wafer 1 during the process and calculating the emissivity uniformity value, the deformation of the wafer 1 can be indirectly characterized, and the measurement of the emissivity will not be affected by the temperature of the wafer 1, and its measured value is accurate and reliable, thereby effectively preventing the wafer 1 from flying due to excessive deformation. Accidents.

[0038] The second aspect of the present invention provides a system for preventing wafer flying, including multiple radiation rate probes 3 and a controller 4. The radiation rate probe 3 is used to collect the radiation rate of the measuring point 2 on the wafer 3. The controller 4 is used to calculate the radiation rate uniformity value according to the radiation rate of the measuring point 2, and judge whether the radiation rate uniformity value is greater than the preset critical threshold value. When the radiation rate uniformity value is greater than the preset critical threshold value, the controller 4 issues an alarm and stops the process. Automatic control can be achieved by setting the controller 4, so as to realize fast calculation, analysis and alarm, and effectively prevent wafer flying accidents. It should be noted that the system is used to execute the method for preventing wafer flying provided by the first aspect of the present invention, which has the same technical effect as the method for preventing wafer flying, and will not be repeated here.

[0039] In an embodiment of the present invention, the controller 4 includes a uniformity calculation module, a judgment and analysis module, and an alarm module, wherein the uniformity calculation module is used to calculate the radiation uniformity value according to the radiation value of the measuring point; the judgment and analysis module is used to compare the radiation uniformity value with the preset critical threshold value to determine whether the radiation uniformity value is greater than the preset critical threshold value; the alarm module is used to alarm when the radiation uniformity value is greater than the preset critical threshold value. In this embodiment, the radiation uniformity value is calculated for the radiation value of each measuring point obtained, and the value can better reflect the deformation amount of the wafer under high temperature state, so that the wafer deformation is analyzed based on the value, so as to accurately determine whether a wafer flying accident will occur, and then the alarm processing can be carried out in time to effectively ensure the safe operation of the equipment. It can be understood that information exchange can be carried out between the above modules.

[0040] A third aspect of the present invention provides a semiconductor device, comprising a system for preventing wafer flying as described in any one of the second aspects above. Figure 3 As shown, taking the RTP device as an example, the device includes a process chamber 5 and a light box 6 arranged at the top opening of the process chamber 5, wherein an edge ring 7 for carrying the wafer 1 is arranged inside the process chamber 5, and the edge ring 7 is arranged above the bottom of the process chamber 5 through a support ring 8, so that the wafer 1 is located at the process position, and a halogen lamp 9 for heating the wafer 1 is arranged above the wafer 1, and the halogen lamp 9 is installed in the light box 6, and three radiation rate probes 3 are arranged below the wafer 1, and the three radiation rate probes 3 are electrically connected to the controller 4 respectively. The semiconductor device has the same technical effect as any one of the embodiments described in the second aspect above, and will not be repeated here.

[0041] In summary, the method, system and semiconductor device for preventing wafer flying provided by the present embodiment have at least the following beneficial technical effects: by selecting multiple measurement points 2 located at different positions on the surface of the wafer 1, the emissivity value of each measurement point 2 during the process is obtained in real time, and the emissivity uniformity value is calculated according to the emissivity value of each measurement point 2, and the emissivity uniformity value is compared with the preset critical threshold value, and when the emissivity uniformity value is greater than the preset critical threshold value, an alarm is issued. This method uses multi-point measurement of emissivity values, and by measuring the emissivity at different positions of the wafer 1 during the process and calculating the emissivity uniformity value, the deformation of the wafer 1 can be indirectly characterized, and the measurement of the emissivity will not be affected by the temperature of the wafer 1, and its measurement value is accurate and reliable, thereby effectively preventing flying accidents caused by excessive deformation of the wafer 1.

[0042] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preventing wafer flying, characterized in that: It includes the following steps: Step 1. Select multiple measurement points at different positions on the wafer surface; Step 2. During the process, the emissivity value of each measuring point is obtained in real time below the wafer; Step 3. Calculate the emissivity uniformity value according to the emissivity value of each measuring point; Step 4: Compare the radiance uniformity value with a preset critical threshold value, and when the radiance uniformity value is greater than the preset critical threshold value, issue an alarm.

2. The method for preventing wafer flying according to claim 1, characterized in that: The calculation formula of the radiance uniformity value is as follows: Emissivity uniformity value = (maximum emissivity - minimum emissivity) / average value of each emissivity.

3. The method for preventing wafer flying according to claim 1, characterized in that: The number of the measuring points is two.

4. The method for preventing wafer flying according to claim 3, characterized in that: The two measuring points are respectively located in the central area of ​​the wafer and the edge area of ​​the wafer.

5. The method for preventing wafer flying according to claim 1, characterized in that: The number of the measuring points is three.

6. The method for preventing wafer flying according to claim 5, characterized in that: The three measuring points are respectively located at a central area of ​​the wafer, a quarter of the diameter of the wafer, and an edge area of ​​the wafer.

7. The method for preventing wafer flying according to claim 1, characterized in that: The step 1 includes: arranging a plurality of radiation rate probes at intervals below the wafer, and arranging the radiation rate probes at intervals from each other.

8. A system for preventing wafer flying, characterized in that: It includes multiple radiometric probes and a controller. The radiometric probe is used to collect the radiometric value of the measuring point on the wafer. The controller is used to calculate the radiometric uniformity value according to the radiometric value of the measuring point and determine whether the radiometric uniformity value is greater than a preset critical threshold. When the radiometric uniformity value is greater than the preset critical threshold, the controller issues an alarm and stops the process.

9. The system for preventing wafer flying according to claim 8, characterized in that: The controller comprises: A uniformity calculation module, used for calculating a radiation uniformity value according to a radiation value of a measurement point; A judgment and analysis module compares the radiation uniformity value with a preset critical threshold value to determine whether the radiation uniformity value is greater than the preset critical threshold value; The alarm module is configured to generate an alarm when the radiation uniformity value is greater than a preset critical threshold.

10. A semiconductor device, characterized in that: It includes the system for preventing wafer flying as claimed in claim 8 or claim 9.

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