Round temperature detection system

Abstract

The invention discloses a circle temperature detection system. Comprising a plurality of LC passive temperature sensors and a reading unit, the LC passive temperature sensor comprises a spiral inductor LS and a sensing capacitor CS which are connected in series; the reading unit comprises a reading inductor L0 and an impedance analyzer; when the temperature of the surface of the wafer where the LC passive temperature sensor is located changes, capacitance and resistance of the sensor can change, so that impedance of the sensor changes, and an impedance analyzer obtains the surface temperature of the wafer by remotely monitoring and analyzing real part values of a resonant frequency value and a maximum impedance value; the precision is higher, the response time is shorter, the compatibility with the integrated circuit manufacturing technology is higher, the power consumption is lower, and the size is smaller; the wafer temperature measurement system adopts a wireless mode, and no cable or lead needs to be connected to the surface of the wafer, so that the reliability and flexibility of temperature measurement are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of wafer temperature monitoring, and in particular relates to a wafer temperature detection system. Background Art

[0002] Monitoring the surface temperature of wafers is of vital importance in the semiconductor chip manufacturing process. The temperature of the wafer directly affects the performance, yield and reliability of semiconductor devices. Accurate temperature monitoring can optimize the manufacturing process, thereby improving device characteristics and reducing defects. By monitoring the surface temperature of the wafer, engineers can gain insight into the thermal profile and identify potential hot spots or thermal changes that may affect device performance and reliability. This information can guide process adjustments, such as optimizing diffusion, deposition and etching steps to improve device uniformity and quality. In addition, temperature monitoring also helps manage the thermal stress that the wafer is subjected to at different production stages, thereby increasing yield and reducing failure rates. In short, accurate monitoring of the surface temperature of the wafer plays a vital role in achieving precise process control, improving device performance and ensuring the long-term reliability of semiconductor devices.

[0003] The common temperature measurement technology currently on the market is to stick or weld contact temperature sensors such as thermocouples on the surface of the wafer, and then lead out its signal wire for subsequent data reception and processing, so as to obtain the surface temperature of the wafer. Thermocouples are made of two different metal wires connected at one end to form a node. When the environment of this junction has a temperature gradient, a voltage signal proportional to the temperature difference will be generated, and then the voltage to temperature conversion is realized by looking up the graduation table. However, various (products) on the market still have various problems.

[0004] refer to Figure 4 , is a thermocouple temperature measurement system in the prior art, mainly composed of a signal conditioning module and a data processing module. The thermocouple first generates a small voltage signal (millivolts) that is proportional to the temperature difference. It is necessary to consider the reference temperature at the connection between the thermocouple wire and the signal conditioning circuit. The cold end compensation circuit can measure the reference temperature and adjust the temperature reading accordingly to ensure the temperature measurement accuracy. The amplifier is used to amplify the output signal of the thermocouple, and the filter can filter out the noise, and then the analog signal is input into the data processing module. The analog signal is converted into a digital signal that can be processed by a microcontroller or computer through an analog-to-digital converter. The microcontroller is responsible for processing the digital temperature data and outputting the temperature signal. It includes functions such as data storage, data display and communication interface to transmit data to external systems.

[0005] The existing technology has the following disadvantages in use:

[0006] The temperature measurement accuracy of the thermocouple itself is low, resulting in large uncertainty in wafer temperature monitoring.

[0007] Since the voltage and temperature of the thermocouple have a nonlinear relationship, a complex signal conditioning circuit must be used, which increases the complexity of the temperature measurement system.

[0008] Thermocouples require the use of leads to lead out signals, causing heat to be conducted along the leads, thereby changing the temperature and airtightness of the measured part of the wafer, introducing contamination, etc.

[0009] To this end, we propose a circular temperature detection system. Summary of the invention

[0010] The object of the present invention is to provide a circle temperature detection system to solve the problems raised in the above background technology.

[0011] To achieve the above object, the present invention provides the following technical solutions: a round temperature detection system, comprising a LC passive temperature sensor and a readout unit, wherein the LC passive temperature sensor is provided in a plurality, and the plurality of the LC passive temperature sensors are embedded in a wafer, so as to obtain the temperature at different positions on the surface of the wafer, and then construct a two-dimensional temperature field of the entire wafer;

[0012] The LC passive temperature sensor includes a spiral inductor L S and a sensing capacitor C S , the spiral inductor L S and the sensing capacitor C S Series connection;

[0013] The readout unit includes a readout inductor L0 and an impedance analyzer. The readout inductor L0 is used to communicate with the spiral inductor L S Mutual inductance, realizing remote collection of the real value of the resonant frequency value and the maximum impedance value, the impedance analyzer obtains the surface temperature of the wafer through the collected real value of the resonant frequency value and the maximum impedance value;

[0014] When the temperature of the wafer surface where the LC passive temperature sensor is located changes, the spiral inductor L of the LC passive temperature sensor S and the sensing capacitor C S The impedance of the LC passive temperature sensor will change, thereby causing the impedance of the LC passive temperature sensor to change. The impedance analyzer is used to remotely monitor and analyze the resonant frequency value and the real part of the maximum impedance value of the LC passive temperature sensor, that is, to obtain the surface temperature of the wafer.

[0015] Furthermore, a spiral inductor L in the LC passive temperature sensor S and a sensing capacitor C S Connected in series, the sensing capacitor C S The expression is:

[0016]

[0017] Where A is the temperature coefficient, ε S0 represents the initial relative dielectric constant, T represents the real-time temperature, T0 represents the initial temperature, ε0 represents the vacuum dielectric constant, S represents the sensing area of ​​the capacitor, and d represents the distance between the two plates of the capacitor.

[0018] Furthermore, the spiral inductor L S There is a parasitic resistance R in series connection S , and the parasitic resistance R S It is related to temperature and the relationship is as follows:

[0019] R S =R S0 [1+α(T-T0)],

[0020] Among them, R S0 is the initial resistance, α is the temperature coefficient of resistance, T represents the real-time temperature, T0 represents the initial temperature, that is, the parasitic resistance R S The resistance value will change with the change of temperature.

[0021] Furthermore, in order to remotely query the LC passive temperature sensor, the readout unit uses inductive coupling to make the impedance of the resonator equivalent to the readout unit, thereby measuring the real part amplitude of the impedance. The input impedance of the LC passive temperature sensor is:

[0022]

[0023] Among them, Z S The impedance value of the resonator equivalent to the readout unit is:

[0024]

[0025] Wherein, R0, L0 and C0 represent the resistance, inductance and capacitance of the readout unit respectively, L S It is represented as a spiral inductor, f is the signal frequency of the impedance analyzer, M is the read inductance L0 and the spiral inductor L S The mutual inductance value.

[0026] Further, the real part of the input impedance is expressed as:

[0027]

[0028] in,

[0029]

[0030] Among them, Q and f Srepresent the quality factor and resonant frequency of the LC passive temperature sensor, respectively, k represents the readout inductance L0 and the spiral inductor L S The coupling coefficient between them.

[0031] Furthermore, the spiral inductor L in the LC passive temperature sensor S The equivalent radius r s Much smaller than the readout inductance L0 and the spiral inductor L S When the coupling distance between them is z, we have:

[0032]

[0033] Wherein, r0 is the equivalent radius of the readout inductor L0 in the readout unit.

[0034] Furthermore, the input impedance Z IN The maximum value of the real part amplitude occurs at the resonant frequency f S Department:

[0035]

[0036] Combination formula R S =R S0 [1+α(T-T0)], further we get:

[0037]

[0038] Furthermore, the input impedance Z IN The maximum value of the real part amplitude is calculated by converting it in combination with the following formula;

[0039]

[0040] get

[0041]

[0042] And in the formula, there are only two unknowns f S andRe(Z IN ) max .

[0043] Furthermore, the input impedance Z IN and the resonant frequency f S The calculation process is based on the following two formulas:

[0044] R S =R S0 [1+α(T-T0)],

[0045]

[0046] The temperature value measured by the LC passive temperature sensor is obtained as follows:

[0047]

[0048] The LC passive temperature sensor is mounted on the surface of the wafer or embedded in the wafer, and then the resonant frequency f of the LC passive temperature sensor is measured by an impedance analyzer. S and the real part of the maximum input impedance Re(Z IN ) max , that is, according to Get the temperature of the wafer surface.

[0049] Furthermore, the LC passive temperature sensor is arranged with a total of 65 temperature measuring points, and 16, 16, 8, 8, 8, 4, 4, and 1 LC passive temperature sensors are arranged in sequence from the edge to the center in a centrally symmetrical and axially symmetrical manner, so as to obtain the temperature at different positions on the wafer surface, and then construct a two-dimensional temperature field of the entire wafer. The intervals between each circle of the LC passive temperature sensors are the same, and the intervals between the LC passive temperature sensors in each circle are also the same.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] When the temperature of the wafer surface where the LC passive temperature sensor is located changes, the capacitance and resistance of the sensor will change, thereby causing the impedance of the sensor to change. The surface temperature of the wafer can be obtained by remotely monitoring and analyzing the resonant frequency value and the real part value of the maximum impedance value of the sensor through an impedance analyzer.

[0052] The LC passive temperature sensor is embedded inside the wafer in a centrally symmetrical and axially symmetrical manner, and the resonant frequency and the real value of the maximum input impedance of the LC passive temperature sensor are wirelessly measured by a readout unit composed of an impedance analyzer and a readout inductor. The temperature measured by the LC passive temperature sensor is calculated according to a formula to obtain the temperature of the wafer surface.

[0053] The temperature of the LC passive temperature sensor, i.e., the temperature of the wafer surface, is obtained by wireless measurement, rather than by connecting with wires or cables, through a readout unit consisting of an impedance analyzer and a readout inductor;

[0054] The present invention adopts an LC passive temperature sensor with higher accuracy, faster response time, higher compatibility with integrated circuit manufacturing technology, lower power consumption and smaller size; the wafer temperature measurement system adopts a wireless form, and no longer needs to connect cables or wires on the wafer surface, thereby improving the reliability and flexibility of temperature measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is the principle diagram of the wafer temperature wireless measurement system of the present invention;

[0056] Figure 2 is an equivalent circuit diagram of the wafer temperature wireless measurement system of the present invention;

[0057] Figure 3 A distribution diagram of the LC passive temperature sensor of the present invention on a wafer;

[0058] Figure 4 The thermocouple temperature measurement system architecture of the prior art. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] See also Figure 1-Figure 3 , the present invention provides a technical solution: a round temperature detection system, comprising a LC passive temperature sensor and a readout unit, wherein the LC passive temperature sensor is provided in a plurality of pieces, and the plurality of the LC passive temperature sensors are embedded in the inside of a wafer, so as to obtain the temperature at different positions on the surface of the wafer, and then construct a two-dimensional temperature field of the entire wafer;

[0061] The LC passive temperature sensor includes a spiral inductor L S and a sensing capacitor C S , the spiral inductor L S and the sensing capacitor C S Series connection;

[0062] The readout unit includes a readout inductor L0 and an impedance analyzer. The readout inductor L0 is used to communicate with the spiral inductor L S Mutual inductance, realizing remote collection of the real value of the resonant frequency value and the maximum impedance value, the impedance analyzer obtains the surface temperature of the wafer through the collected real value of the resonant frequency value and the maximum impedance value;

[0063] When the temperature of the wafer surface where the LC passive temperature sensor is located changes, the spiral inductor L of the LC passive temperature sensor S and the sensing capacitor C SThe impedance of the LC passive temperature sensor will change, thereby causing the impedance of the LC passive temperature sensor to change. The impedance analyzer is used to remotely monitor and analyze the resonant frequency value and the real part of the maximum impedance value of the LC passive temperature sensor, that is, to obtain the surface temperature of the wafer.

[0064] In order to realize the sensing capacitor C in the LC passive temperature sensor S In this embodiment, preferably, a spiral inductor L in the LC passive temperature sensor S and a sensing capacitor C S Connected in series, the sensing capacitor C S The expression is:

[0065]

[0066] Where A is the temperature coefficient, ε S0 represents the initial relative dielectric constant, T represents the real-time temperature, T0 represents the initial temperature, ε0 represents the vacuum dielectric constant, S represents the sensing area of ​​the capacitor, and d represents the distance between the two plates of the capacitor.

[0067] In order to achieve the parasitic resistance R S The resistance value is calculated and processed. In this embodiment, preferably, the spiral inductor L S There is a parasitic resistance R in series connection S , and the parasitic resistance R S It is related to temperature and the relationship is as follows:

[0068] R S =R S0 [1+α(T-T0)],

[0069] Among them, R S0 is the initial resistance, α is the temperature coefficient of resistance, T represents the real-time temperature, T0 represents the initial temperature, that is, the parasitic resistance R S The resistance value will change with the change of temperature.

[0070] In order to calculate the input impedance of the LC passive temperature sensor, in this embodiment, preferably, the readout unit uses inductive coupling to make the impedance of the resonator equivalent to the readout unit in order to remotely query the LC passive temperature sensor, thereby measuring the real part amplitude of the impedance. The input impedance of the LC passive temperature sensor is:

[0071]

[0072] Among them, Z S The impedance value of the resonator equivalent to the readout unit is:

[0073]

[0074] Wherein, R0, L0 and C0 represent the resistance, inductance and capacitance of the readout unit respectively, L S It is represented as a spiral inductor, f is the signal frequency of the impedance analyzer, M is the read inductance L0 and the spiral inductor L S The mutual inductance value.

[0075] In order to collect the real part of the input impedance, in this embodiment, preferably, the real part of the input impedance is expressed as:

[0076]

[0077] in,

[0078]

[0079] Among them, Q and f S represent the quality factor and resonant frequency of the LC passive temperature sensor, respectively, k represents the readout inductance L0 and the spiral inductor L S The coupling coefficient between them.

[0080] In order to realize the readout inductance L0 and spiral inductor L S In this embodiment, preferably, the spiral inductor L in the LC passive temperature sensor S The equivalent radius r s Much smaller than the readout inductance L0 and the spiral inductor L S When the coupling distance between them is z, we have:

[0081]

[0082] Wherein, r0 is the equivalent radius of the readout inductor L0 in the readout unit.

[0083] In order to achieve the input impedance Z IN The maximum value of the real part amplitude is calculated and processed. In this embodiment, preferably, the input impedance Z IN The maximum value of the real part amplitude occurs at the resonant frequency f S Department:

[0084]

[0085] Combination formula R S =R S0 [1+α(T-T0)], further we get:

[0086]

[0087] In order to achieve the input impedance Z IN The maximum value of the real part amplitude is converted and calculated. In this embodiment, preferably, the input impedance Z IN The maximum value of the real part amplitude is calculated by converting it in combination with the following formula;

[0088]

[0089] get

[0090]

[0091] And in the formula, there are only two unknowns f S andRe(Z IN ) max .

[0092] In order to enable the LC passive temperature sensor to achieve temperature measurement, in this embodiment, preferably, the input impedance Z IN and the resonant frequency f S The calculation process is based on the following two formulas:

[0093] R S =R S0 [1+α(T-T0)],

[0094]

[0095] The temperature value measured by the LC passive temperature sensor is obtained as follows:

[0096]

[0097] The LC passive temperature sensor is mounted on the surface of the wafer or embedded in the wafer, and then the resonant frequency f of the LC passive temperature sensor is measured by an impedance analyzer. S and the real part of the maximum input impedance Re(Z IN ) max , that is, according to Get the temperature of the wafer surface.

[0098] In order to realize temperature detection of the wafer and realize equal detection, and realize all-round temperature detection of the wafer, in this embodiment, preferably, the LC passive temperature sensor is arranged with a total of 65 temperature measurement points, and 16, 16, 8, 8, 8, 4, 4, and 1 LC passive temperature sensors are arranged from the edge to the center in a centrally symmetrical and axially symmetrical manner, so as to obtain the temperature at different positions on the wafer surface, and then construct a two-dimensional temperature field of the entire wafer, the intervals between each circle of the LC passive temperature sensors are the same, and the intervals between the LC passive temperature sensors in each circle are also the same.

[0099] The working principle and use process of the present invention:

[0100] When the temperature of the wafer surface where the LC passive temperature sensor is located changes, the capacitance and resistance of the sensor will change, resulting in a change in the impedance of the sensor. The surface temperature of the wafer can be obtained by remotely monitoring and analyzing the resonant frequency value and the real part of the maximum impedance value of the sensor through an impedance analyzer.

[0101] In the sensor, a spiral inductor L S and a sensing capacitor C S Series connection; sensing capacitor C S The expression is:

[0102]

[0103] Where A is the temperature coefficient, ε S0 represents the initial relative dielectric constant, T represents the real-time temperature, T0 represents the initial temperature, ε0 represents the vacuum dielectric constant, S represents the sensing area of ​​the capacitor, and d represents the distance between the two plates of the capacitor; spiral inductor L S The parasitic resistance R S Temperature related:

[0104] R S =R S0 [1+α(T-T0)] (2)

[0105] Among them, R S0 is the initial resistance, α is the temperature coefficient of resistance;

[0106] In order to remotely interrogate the sensor, the impedance of the resonator can be equivalent to the readout unit by inductive coupling, so as to measure the real amplitude of the impedance; the input impedance of the LC passive temperature sensor is:

[0107]

[0108] Among them, Z S The impedance value of the resonator equivalent to the readout unit is:

[0109]

[0110] Wherein, R0, L0 and C0 represent the resistance, inductance and capacitance of the readout unit respectively; L S represents the inductance in the sensor, f is the signal frequency of the impedance analyzer, and M is the spiral inductor L S And read the mutual inductance value of inductor L0;

[0111] The real part of the impedance can be expressed as:

[0112]

[0113] in,

[0114]

[0115] Among them, Q and f S They represent the quality factor and resonant frequency of the LC passive temperature sensor respectively, and k represents the coupling coefficient between the two inductors. When the inductor coil L in the LC passive temperature sensor S The equivalent radius r s When it is much smaller than the coupling distance z between the two inductors, we have:

[0116]

[0117] Where r0 is the equivalent radius of the inductor L0 in the readout unit; the input impedance Z IN The maximum value of the real part amplitude occurs at the resonant frequency f S Department:

[0118]

[0119] Combining equations (2) to (8), we can further obtain:

[0120]

[0121] By rearranging equations (5) and (8), we can obtain

[0122]

[0123] In equations (10) and (11), there are only two unknowns f S andRe(Z IN ) max Combining equations (2) and (11), the temperature value measured by the LC passive temperature sensor can be obtained as follows:

[0124]

[0125] In summary, it can be seen that the LC passive temperature sensor only needs to be installed on the wafer surface or embedded inside the wafer, and then the resonant frequency f of the LC passive temperature sensor is measured by an impedance analyzer. S and the real part of the maximum input impedance Re(Z IN ) max , the temperature of the wafer surface can be obtained according to formula (12);

[0126] Multiple LC passive temperature sensors are embedded into the wafer, with a total of 65 temperature measurement points. 16, 16, 8, 8, 8, 4, 4, and 1 LC passive temperature sensors are arranged at equal intervals from the edge to the center in a centrally symmetrical and axially symmetrical manner, so as to obtain the temperature at different positions on the surface and reconstruct the two-dimensional temperature field of the entire wafer.

[0127] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A circular temperature detection system, comprising an LC passive temperature sensor and a readout unit, characterized in that: The LC passive temperature sensors are provided in a plurality, and the plurality of LC passive temperature sensors are embedded in the wafer, so as to obtain the temperature at different positions on the surface of the wafer, and then construct a two-dimensional temperature field of the entire wafer; The LC passive temperature sensor includes a spiral inductor L S and a sensing capacitor C S , the spiral inductor L S and the sensing capacitor C S Series connection; The readout unit includes a readout inductor L0 and an impedance analyzer. The readout inductor L0 is used to communicate with the spiral inductor L S Mutual inductance, realizing remote collection of the real value of the resonant frequency value and the maximum impedance value, the impedance analyzer obtains the surface temperature of the wafer through the collected real value of the resonant frequency value and the maximum impedance value; When the temperature of the wafer surface where the LC passive temperature sensor is located changes, the spiral inductor L of the LC passive temperature sensor S and the sensing capacitor C S The impedance of the LC passive temperature sensor will change, thereby causing the impedance of the LC passive temperature sensor to change. The impedance analyzer is used to remotely monitor and analyze the resonant frequency value and the real part of the maximum impedance value of the LC passive temperature sensor, that is, to obtain the surface temperature of the wafer.

2. A circular temperature detection system according to claim 1, characterized in that: The LC passive temperature sensor has a spiral inductor L S and a sensing capacitor C S Connected in series, the sensing capacitor C S The expression is: Where A is the temperature coefficient, ε S0 represents the initial relative dielectric constant, T represents the real-time temperature, T0 represents the initial temperature, ε0 represents the vacuum dielectric constant, S represents the sensing area of ​​the capacitor, and d represents the distance between the two plates of the capacitor.

3. A circular temperature detection system according to claim 2, characterized in that: The spiral inductor L S There is a parasitic resistance R in series connection S , and the parasitic resistance R S It is related to temperature and the relationship is as follows: R S =R S0 [1+α(T-T0)], Among them, R S0 is the initial resistance, α is the temperature coefficient of resistance, T represents the real-time temperature, T0 represents the initial temperature, that is, the parasitic resistance R S The resistance value will change with the change of temperature.

4. A circular temperature detection system according to claim 3, characterized in that: In order to remotely query the LC passive temperature sensor, the readout unit uses inductive coupling to make the impedance of the resonator equivalent to the readout unit, thereby measuring the real amplitude of the impedance. The input impedance of the LC passive temperature sensor is: Among them, Z S The impedance value of the resonator equivalent to the readout unit is: Wherein, R0, L0 and C0 represent the resistance, inductance and capacitance of the readout unit respectively, L S It is represented as a spiral inductor, f is the signal frequency of the impedance analyzer, M is the read inductance L0 and the spiral inductor L S The mutual inductance value.

5. A circular temperature detection system according to claim 4, characterized in that: The real part of the input impedance is expressed as: in, Among them, Q and f S represent the quality factor and resonant frequency of the LC passive temperature sensor, respectively, k represents the readout inductance L0 and the spiral inductor L S The coupling coefficient between them.

6. A circular temperature detection system according to claim 5, characterized in that: The spiral inductor L in the LC passive temperature sensor S The equivalent radius r s Much smaller than the readout inductance L0 and the spiral inductor L S When the coupling distance between them is z, we have: Wherein, r0 is the equivalent radius of the readout inductor L0 in the readout unit.

7. A circular temperature detection system according to claim 6, characterized in that: The input impedance Z IN The maximum value of the real part amplitude occurs at the resonant frequency f S Department: Combination formula R S =R S0 [1+α(T-T0)], further we get:

8. A circular temperature detection system according to claim 7, characterized in that: The input impedance Z IN The maximum value of the real part amplitude is calculated by combining the following formula for conversion; get And in the formula, there are only two unknowns f S andRe(Z IN ) max .

9. A circular temperature detection system according to claim 7, characterized in that: The input impedance Z IN and the resonant frequency f S The calculation process is based on the following two formulas: R S =R S0 [1+α(T-T0)], The temperature value measured by the LC passive temperature sensor is obtained as follows: The LC passive temperature sensor is mounted on the surface of the wafer or embedded in the wafer, and then the resonant frequency f of the LC passive temperature sensor is measured by an impedance analyzer. S and the real part of the maximum input impedance Re(Z IN ) max , that is, according to Get the temperature of the wafer surface.

10. A circular temperature detection system according to claim 1, characterized in that: The LC passive temperature sensor is arranged with a total of 65 temperature measuring points, and 16, 16, 8, 8, 8, 4, 4, and 1 LC passive temperature sensors are arranged in sequence from the edge to the center in a centrally symmetrical and axially symmetrical manner, so as to obtain the temperature at different positions on the wafer surface, and then construct a two-dimensional temperature field of the entire wafer. The intervals between each circle of the LC passive temperature sensors are the same, and the intervals between the LC passive temperature sensors in each circle are also the same.

Images