Fixed charge monitoring method, monitoring device and process temperature regulation and control system
By measuring the C-V curve of the gate oxide layer, the charge amount of fixed charge is determined and the process temperature is adjusted when the charge amount is abnormal, the problem of process temperature abnormality in semiconductor processes is solved, and device reliability and production line stability are improved.
Patent Information
- Application Number
- CN202411614637.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-13
- Publication Date
- 2025-02-18
AI Technical Summary
In semiconductor processes, the process temperature abnormalities of the gate oxide layer are not monitored in time, which will affect the reliability of the device and the stability of the production line.
By measuring the first C-V curve and the second C-V curve of the gate oxide layer, the charge amount in which the fixed charge is fixed is determined, and a control signal is outputted outside the threshold range to adjust the process temperature.
Real-time monitoring of the process temperature of the gate oxide layer is realized, abnormalities are discovered in a timely manner, and production line stability and device reliability are improved.
Smart Images
Figure CN119480630A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of semiconductor process equipment, and in particular, relates to a fixed charge monitoring method, a monitoring device, and a process temperature control system. Background Art
[0002] In the field of semiconductor technology, the gate oxide process to generate the gate oxide layer is a crucial process, which is usually carried out in a high temperature environment. For example, silicon-based semiconductor devices are usually carried out at 800°C to 1100°C, and silicon carbide semiconductor devices are usually carried out at 1350°C. If the process is abnormal but not monitored in time, the abnormal process will affect the relevant parameters and performance of the device, and reduce the reliability of the device and the stability of the production line. For this reason, the charge amount of the fixed charge in the gate oxide layer can be measured to reflect whether the process temperature of the gate oxide layer is abnormal.
[0003] Based on this, how to achieve timely monitoring of fixed charges has become a research direction in the field of semiconductor process equipment technology. Summary of the invention
[0004] The present application proposes a fixed charge monitoring method, a monitoring device and a process temperature control system, aiming to realize the monitoring of fixed charge.
[0005] In a first aspect, an embodiment of the present application provides a method for monitoring fixed charge, the monitoring method comprising: determining a first CV curve of a gate oxide layer, and determining a second CV curve of the gate oxide layer after heat treatment. According to the first CV curve and the second CV curve, the charge amount of the fixed charge in the gate oxide layer is determined. When the charge amount of the fixed charge is outside a threshold range, a control signal is output.
[0006] In some embodiments, when the process temperatures of the multiple gate oxide layers all meet the preset temperature, the third CV curves of the multiple gate oxide layers before the heat treatment are determined, and the fourth CV curves of the multiple gate oxide layers after the heat treatment are determined. According to the third CV curves and the fourth CV curves of the multiple gate oxide layers, the charge amounts of the fixed charges in the multiple gate oxide layers are determined. The minimum value of the charge amounts of the multiple fixed charges is used as the lower limit value of the above threshold range, and the maximum value of the charge amounts of the multiple fixed charges is used as the upper limit value of the above threshold range.
[0007] In some embodiments, under the control of the control signal, an alarm is issued to adjust the process temperature of the gate oxide layer.
[0008] In some embodiments, under the control of the control signal, an indication image for adjusting the process temperature of the gate oxide layer is displayed.
[0009] In some embodiments, the first CV curve and the second CV curve are determined in a non-contact manner.
[0010] In some embodiments, the process temperature range of the above heat treatment is: 300°C~350°C; the process time is 30 minutes.
[0011] In the embodiment of the present application, the first CV curve and the second CV curve of the gate oxide layer before and after the heat treatment are determined, and the charge amount of the fixed charge in the gate oxide layer is determined according to the first CV curve and the second CV curve. By judging whether the charge amount of the fixed charge is within the threshold range, it is judged whether the process temperature of the gate oxide layer is abnormal. Based on this, the embodiment of the present application can test the entire wafer during the preparation process, without waiting until the preparation is completed to perform the test, and the test method is relatively simple. By real-time monitoring of the charge amount of the fixed charge in the gate oxide layer, it is possible to promptly detect whether the process temperature is abnormal, which is conducive to improving the stability of the production line, and thus improving the reliability of the device.
[0012] In a second aspect, an embodiment of the present application further provides a fixed charge monitoring device, which includes a CV test device and a monitor. The CV test device is used to determine a first CV curve of the gate oxide layer before heat treatment, and a second CV curve of the gate oxide layer after heat treatment. The monitor is electrically connected to the CV test device, and the monitor is used to determine the charge amount of the fixed charge in the gate oxide layer according to the first CV curve and the second CV curve, and output a control signal when the charge amount of the fixed charge is outside the threshold range.
[0013] In some embodiments, the monitor includes a calculation unit and a control unit. The calculation unit is electrically connected to the CV test device, and the calculation unit is used to determine the charge amount of the fixed charge in the gate oxide layer according to the first CV curve and the second CV curve. The control unit is electrically connected to the calculation unit, and the control unit is used to determine whether the charge amount of the fixed charge is within a threshold range, and if not, output a control signal.
[0014] In some embodiments, the CV testing device is a non-contact CV testing device.
[0015] In the embodiment of the present application, a CV test device is used to determine a first CV curve of the gate oxide layer before heat treatment, and a second CV curve of the gate oxide layer after heat treatment, and a monitor is electrically connected to the CV test device. The monitor can determine the charge amount of the fixed charge in the gate oxide layer according to the first CV curve and the second CV curve, and judge whether the charge amount of the fixed charge is within the threshold range, thereby realizing the quality monitoring of the gate oxide layer, and judging whether the process temperature of the gate oxide layer is abnormal. The CV test device can perform measurements in time after the gate oxide process is completed, and the measurement process is simple, and it is not necessary to wait for the preparation process to be completed before the measurement can be performed, and there is no need to make the corresponding metal or polycrystalline gate electrode, and it is non-destructive to the device. Compared with the contact measurement in the related art, the embodiment of the present application can test the entire wafer during the preparation process, and will not contaminate the product, which is beneficial to the reliability of the device.
[0016] In a third aspect, an embodiment of the present application further provides a process temperature control system, the control system comprising any one of the monitoring devices mentioned in the second aspect, and process equipment. The process equipment is configured to adjust the process temperature of the gate oxide layer when the monitoring device determines that the charge amount of the fixed charge in the gate oxide layer is outside the threshold range.
[0017] In the embodiment of the present application, when the monitoring device monitors that the charge amount of the fixed charge is outside the threshold range, it indicates that the process temperature of the gate oxide layer is abnormal, and the device parameters and related performance do not meet the process requirements. In this case, the process temperature of the gate oxide layer can be adjusted to improve the stability of the production line and the reliability of the device.
[0018] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 A flow chart of a method for monitoring fixed charge provided in an embodiment of the present application; Figure 2 A structural block diagram of a monitoring device provided in an embodiment of the present application; Figure 3 Another structural block diagram of the monitoring device provided in the embodiment of the present application; Figure 4 Another structural block diagram of the monitoring device provided in the embodiment of the present application; Figure 5 Another structural block diagram of the monitoring device provided in the embodiment of the present application; Figure 6 This is a structural block diagram of the process temperature control system provided in an embodiment of the present application. DETAILED DESCRIPTION
[0020] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.
[0021] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.
[0022] In the description of the present application, “plurality” means two or more.
[0023] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.
[0024] When describing some embodiments, the expression "connected" and its derivatives may be used. The term "connected" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. The term "electrically connected" indicates, for example, that two or more components are in direct physical or electrical contact, and may also mean that two or more components are not in direct contact with each other, but still cooperate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents of this document.
[0025] In the field of semiconductor technology, the gate oxide process to generate a gate oxide layer is a crucial process flow. The process of the gate oxide layer affects the performance of semiconductor devices, and then affects the use effect of the chip. By measuring the relevant parameters of the semiconductor device, the relevant problems in the process can be reflected. For example, in the relevant technology, an offline contact CV measurement method can be used to measure the charge amount of the fixed charge in the gate oxide layer. However, since the measurement method is contact-type, it will cause certain damage to the device or cause certain pollution to the device. Moreover, in the relevant technology, the measurement method is to measure after the corresponding metal or polycrystalline gate electrode is made. The test requires more equipment, the process is complicated, and the problem feedback is not timely.
[0026] To solve the above problems, the embodiments of the present application provide a method for monitoring a fixed charge, such as Figure 1 As shown, Figure 1 A flow chart of a method for monitoring fixed charge provided in an embodiment of the present application.
[0027] like Figure 1 As shown, the fixed charge monitoring method includes the following steps S01-S04: Step S01: determining a first CV curve of a gate oxide layer.
[0028] Step S02: determining a second CV curve of the gate oxide layer after the thermal treatment.
[0029] For example, in some embodiments, the process temperature range of the above heat treatment is 300°C to 350°C, and the process time is 30 minutes. It should be noted that 30 minutes here can be understood as about 30 minutes, for example, 25 minutes to 35 minutes. The process time can meet the requirements within a reasonable error range.
[0030] The gate oxide layer generated by dry oxygen oxidation has a certain amount of movable charge and fixed charge in the gate oxide layer before heat treatment. The existence of movable charge causes capacitance and voltage to be generated in the gate oxide layer. The first CV curve of the gate oxide layer before heat treatment is determined by CV testing equipment. The first CV curve can be used to calculate the charge amount of the movable charge before heat treatment.
[0031] After the heat treatment, the fixed charges in the gate oxide layer can be activated and converted into movable charges. The second CV curve of the gate oxide layer after the heat treatment is determined by a CV testing device. The second CV curve can be used to calculate the charge amount of the movable charges after the heat treatment, which is the total amount of the movable charges and the fixed charges before the heat treatment.
[0032] In some embodiments, a non-contact method, such as using a non-contact CV testing device, can be used to measure a first CV curve of a gate oxide layer generated by dry oxygen oxidation before heat treatment and a second CV curve of the gate oxide layer after heat treatment.
[0033] Since the non-contact CV testing equipment can test the entire wafer after the gate oxide layer is formed and adopts a non-contact principle, the monitoring method can achieve detection without the need to make corresponding metal or polycrystalline gate electrodes. The operation is relatively simple and timely, which is conducive to quickly discovering problems and improving efficiency, thereby improving the stability of the production line.
[0034] Step S03: Determine the amount of fixed charges in the gate oxide layer according to the first CV curve and the second CV curve.
[0035] Exemplarily, the charge amount of the movable charge of the gate oxide layer before heat treatment is determined according to the first CV curve, and the charge amount of the movable charge of the gate oxide layer after heat treatment is determined according to the second CV curve. Since the charge amount of the movable charge after the heat treatment is the total amount of the movable charge and the fixed charge before the heat treatment, the difference between the movable charge of the gate oxide layer before and after the heat treatment is the "charge amount of the fixed charge of the gate oxide layer before heat treatment".
[0036] Step S04: When the charge amount of the fixed charge is outside the threshold range, a control signal is output.
[0037] The threshold range here can be obtained by analyzing historical data. For example, in some embodiments, similar to the process of steps S01 to S02 above, when the process temperatures of multiple gate oxide layers all meet the preset temperature, the third CV curves of multiple gate oxide layers before heat treatment are determined, and the fourth CV curves of multiple gate oxide layers after heat treatment are determined. Then, based on the third CV curves and the fourth CV curves of the multiple gate oxide layers, the charge amounts of the fixed charges in the multiple gate oxide layers are determined. The minimum value of the charge amounts of the multiple fixed charges is used as the lower limit value of the above threshold range, and the maximum value of the charge amounts of the multiple fixed charges is used as the upper limit value of the above threshold range.
[0038] The threshold range thus obtained can be used as a basis for judgment. When the charge amount of the fixed charge in the gate oxide layer falls outside the threshold range, it can be determined that the process temperature for forming the gate oxide layer does not meet the requirements.
[0039] By performing multiple measurements and calculations when the process temperatures all meet the preset temperatures, sufficient data can be obtained, which is beneficial to improving the authenticity and accuracy of the threshold range, and further beneficial to improving the accuracy of the monitoring method that uses this threshold range as the basis for judgment.
[0040] Illustratively, in some embodiments, under the control of the control signal, an alarm is issued to adjust the process temperature of the gate oxide layer.
[0041] In some embodiments, under the control of the control signal, an indication image for adjusting the process temperature of the gate oxide layer is displayed.
[0042] The above alarm information or indication image information can be used to remind operators to respond quickly. When confirming that the process temperature of the gate oxide layer is abnormal, the process temperature can be adjusted in time, problems can be discovered and solved in time, and the stability of the production line can be improved.
[0043] Based on this, the monitoring method provided in the embodiment of the present application can test the entire wafer during the preparation process without having to wait until the preparation is completed to perform testing. In addition, the testing method is relatively simple and can promptly detect whether the process temperature is abnormal, which is beneficial to improving the stability of the production line and thereby improving the reliability of the device.
[0044] On the other hand, the embodiment of the present application also provides a fixed charge monitoring device, such as Figure 2 As shown, Figure 2 A structural block diagram of a monitoring device provided in an embodiment of the present application.
[0045] like Figure 2 As shown, the monitoring device 100 includes a CV test device 110 and a monitor 120. The CV test device 110 is used to measure and determine a first CV curve of the gate oxide layer before heat treatment, and a second CV curve of the gate oxide layer after heat treatment. The monitor 120 is electrically connected to the CV test device 110, and the monitor 120 is used to calculate the charge amount of the fixed charge in the gate oxide layer according to the first CV curve and the second CV curve, and output a control signal when the charge amount of the fixed charge is outside the threshold range.
[0046] For example, after the CV testing device 110 measures and determines the first CV curve, it can actively transmit a first data signal containing the first CV curve to the monitor 120, or the monitor 120 actively collects the first data signal containing the first CV curve from the CV testing device 110. Similarly, after the CV testing device 110 measures and determines the second CV curve, it can actively transmit a second data signal containing the second CV curve to the monitor 120, or the monitor 120 actively collects the second data signal containing the second CV curve from the non-contact CV testing device 110.
[0047] The monitor 120 calculates the charge amount of the movable charge of the gate oxide layer before the heat treatment based on the first CV curve, and calculates the charge amount of the movable charge of the gate oxide layer after the heat treatment based on the second CV curve. Since the charge amount of the movable charge after the heat treatment is the total amount of the movable charge and the fixed charge before the heat treatment, the difference between the movable charge of the gate oxide layer before and after the heat treatment is the "charge amount of the fixed charge of the gate oxide layer before the heat treatment".
[0048] When the process temperature of the gate oxide layer meets the process requirements, the charge amount of the fixed charge in the gate oxide layer will fluctuate within a numerical range, namely the above-mentioned "threshold range". If the monitor 120 determines that the charge amount of the fixed charge is within the threshold range, it indicates that the process temperature of the gate oxide layer meets the process requirements; if the monitor 120 determines that the charge amount of the fixed charge is outside the threshold range, it indicates that the process temperature of the gate oxide layer does not meet the process requirements.
[0049] In the embodiment of the present application, the CV test device 110 is used to determine the first CV curve and the second CV curve of the gate oxide layer before and after the heat treatment, and the monitor 120 is used to determine the charge amount of the fixed charge in the gate oxide layer according to the first CV curve and the second CV curve, and to judge whether the charge amount of the fixed charge is within the threshold range, thereby achieving real-time monitoring of the fixed charge, and further achieving quality monitoring of the gate oxide layer. The CV test device can perform measurements in a timely manner after the gate oxide process is completed, and the measurement process is simple, and it is not necessary to wait for the preparation process to be completed before the measurement can be performed, and there is no need to make the corresponding metal or polycrystalline gate electrode, and it is non-destructive to the device. Compared with the contact measurement in the related art, the embodiment of the present application can test the entire wafer during the preparation process, and will not contaminate the product, which is beneficial to the reliability of the device.
[0050] When the charge amount of the fixed charge is outside the threshold range, the monitor 120 may output a control signal to alert the operator.
[0051] For example, in some embodiments, Figure 3 As shown, Figure 3 Another structural block diagram of the monitoring device provided in an embodiment of the present application.
[0052] The monitor 120 includes a calculation unit 121 and a control unit 122. The calculation unit 121 is electrically connected to the CV test device 110, and the calculation unit 121 is used to determine the charge amount of the fixed charge in the gate oxide layer according to the first CV curve and the second CV curve. The control unit 122 is electrically connected to the calculation unit 121, and the calculation unit 121 can transmit a data signal containing the charge amount of the fixed charge to the control unit 122, or the control unit 122 collects the data signal containing the charge amount of the fixed charge, and then the control unit 122 determines whether the charge amount of the fixed charge is within a threshold range. If the control unit 122 determines that the charge amount of the fixed charge is outside the threshold range, it outputs a control signal.
[0053] For example, Figure 4~Figure 5 As shown, Figure 4 Another structural block diagram of the monitoring device provided in the embodiment of the present application is shown in FIG. Figure 5 Another structural block diagram of the monitoring device provided in the embodiment of the present application.
[0054] like Figure 4 As shown, in some embodiments, the monitoring device 100 further includes an alarm 130. Under the control of a control signal, the alarm 130 issues an alarm for adjusting the process temperature of the gate oxide layer to remind the operator to handle it in time.
[0055] like Figure 5 As shown, in some embodiments, the monitoring device 100 further includes a display 140. Under the control of a control signal, the display 140 displays an indication image of adjusting the process temperature of the gate oxide layer to remind the operator to handle it in time.
[0056] In the above embodiment, the charge amount of the fixed charge is calculated by the calculation unit 121, and the control unit 122 determines whether the charge amount of the fixed charge is within the threshold range, and when the control unit 122 determines that the charge amount of the fixed charge is outside the threshold range, it will output a control signal. The above settings realize real-time monitoring of the charge amount of the fixed charge in the gate oxide layer, and can promptly detect whether there is an abnormality in the process temperature of the gate oxide layer, which is beneficial to improving the stability of the process production line.
[0057] In a third aspect, the present application also provides a process temperature control system. Figure 6 This is a structural block diagram of the process temperature control system provided in an embodiment of the present application.
[0058] In some embodiments, Figure 6 As shown, the control system 300 includes a monitoring device 100 and a process equipment 200 .
[0059] When the monitor 120 of the monitoring device 100 determines that the charge amount of the fixed charge is outside the threshold range, the monitor 120 sends a control signal and then adjusts the process temperature of the gate oxide layer through the process equipment 200 so that the process temperature of the gate oxide layer meets the process requirements again.
[0060] For example, the process equipment 200 may be independent of the monitoring device 100 , and after observing the alarm signal or indication image, the on-site staff may manually control the process equipment 200 to make corresponding temperature adjustments to reach the target temperature.
[0061] Exemplarily, the process equipment 200 may also be electrically connected to the monitor 120 in the monitoring device 100 , and perform corresponding temperature adjustments after receiving a control signal from the monitor 120 .
[0062] In the embodiment of the present application, the control system 300 performs real-time monitoring of the charge amount of the fixed charge through the monitoring device 100. When the charge amount of the fixed charge is outside the threshold range, the control signal output by the monitoring device 100 can promptly reflect that the process temperature is in an abnormal state, and then the corresponding temperature adjustment is performed through the process equipment 200. This system achieves the purpose of real-time monitoring of the process temperature of the gate oxide layer, thereby improving the process stability of the gate oxide layer, and further improving the reliability of devices processed by the gate oxide process.
[0063] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the claims and their equivalents.
Claims
1. A method for monitoring fixed charge in a gate oxide process, characterized in that: include: Determining a first CV curve of a gate oxide layer; Determining a second CV curve of the gate oxide layer after thermal treatment; Determining the amount of fixed charges in the gate oxide layer according to the first CV curve and the second CV curve; When the charge amount of the fixed charge is outside the threshold range, a control signal is output.
2. The monitoring method according to claim 1, characterized in that: When the process temperatures of the plurality of gate oxide layers all meet the preset temperature, determining third CV curves of the plurality of gate oxide layers before heat treatment, and determining fourth CV curves of the plurality of gate oxide layers after heat treatment; According to the third CV curve and the fourth CV curve of the plurality of gate oxide layers, the charge amounts of the fixed charges in the plurality of gate oxide layers are determined; the minimum value among the charge amounts of the plurality of fixed charges is used as the lower limit value of the threshold range, and the maximum value among the charge amounts of the plurality of fixed charges is used as the upper limit value of the threshold range.
3. The monitoring method according to claim 1 or 2, characterized in that: Under the control of the control signal, an alarm is issued to adjust the process temperature of the gate oxide layer.
4. The monitoring method according to claim 1 or 2, characterized in that: Under the control of the control signal, an indication image for adjusting the process temperature of the gate oxide layer is displayed.
5. The monitoring method according to claim 1, characterized in that: The first CV curve and the second CV curve are determined in a non-contact manner.
6. The monitoring method according to claim 1, characterized in that: The process temperature range of the heat treatment is: 300°C~350°C; the process time is 30 minutes.
7. A fixed charge monitoring device, characterized in that: Used to execute the monitoring method according to any one of claims 1 to 6, the monitoring device comprises: A CV testing device, used to determine a first CV curve of a gate oxide layer before heat treatment, and a second CV curve of the gate oxide layer after heat treatment; A monitor is electrically connected to the CV test device, and is used to determine the charge amount of the fixed charge in the gate oxide layer according to the first CV curve and the second CV curve, and output a control signal when the charge amount of the fixed charge is outside a threshold range.
8. The monitoring device according to claim 7, characterized in that: The monitor comprises: A calculation unit, electrically connected to the CV test device, and configured to determine the amount of fixed charges in the gate oxide layer according to the first CV curve and the second CV curve; A control unit is electrically connected to the calculation unit, and is used to determine whether the charge amount of the fixed charge is within a threshold range, and if not, output a control signal.
9. The monitoring device according to claim 7, characterized in that: The CV testing device is a non-contact CV testing device.
10. A process temperature control system, characterized in that: include: The monitoring device according to any one of claims 7 to 9; The process equipment is configured to adjust the process temperature of the gate oxide layer when the monitoring device determines that the charge amount of the fixed charge in the gate oxide layer is outside the threshold range.