ATC System and Control Method for Chip Testing

Abstract

This application relates to an ATC system and control method for chip testing. It acquires the temperature value collected by a temperature acquisition device in a heat-conducting structure in real time, and analyzes the initial and real-time errors based on the set operating temperature. When the cascade adjustment conditions are met based on the initial and real-time error analysis, the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop are cascaded. When the preset cascade adjustment conditions are not met, the thermal compensation power of the heat-conducting structure is adjusted in a single loop. Cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop when the initial and real-time errors meet the cascade adjustment conditions effectively solves the problem of large overshoot caused by excessive instantaneous power during chip testing, thus improving test reliability.

Description

Technical Field

[0001] This application relates to the field of semiconductor testing technology, and in particular to an ATC system and control method for chip testing. Background Technology

[0002] The ATC (Active Thermal Control) system used for chip temperature failure testing typically has two temperature sources (one cold source and one hot source). The heat source is provided by an electric heating element in the thermally conductive structure, while the cold source is provided by a refrigerator. When the chip test temperature rises at the start, the ATC system keeps the cold source constant and monitors the temperature value at the outlet of the flow channel in the refrigerator to maintain a constant superheat at the outlet of the flow channel, thus keeping the heat exchange between the flow channel and the upper surface of the thermally conductive structure constant.

[0003] Traditional ATC system heat source control methods adjust the heating duty cycle of the electric heating element by monitoring the temperature value of the control point to keep the temperature of the control point constant. However, if the power of the pressed chip is too high, the real-time temperature of the control point exceeds the set threshold, that is, the overshoot exceeds the required value. It is impossible to quickly and effectively suppress the overshoot. During chip testing, the problem of large overshoot is easily caused by the instantaneous power being too high, resulting in low test reliability. Summary of the Invention

[0004] Therefore, it is necessary to provide an ATC system and control method for chip testing that can improve testing reliability in response to the above problems.

[0005] The first aspect of this application provides a control method for an ATC system used for chip testing, comprising:

[0006] The temperature value collected by the temperature acquisition device in the heat-conducting structure is obtained in real time; the heat-conducting structure is set between the circulation loop of the chip testing ATC system and the chip under test.

[0007] The initial error and real-time error are obtained based on the temperature value and the set operating temperature.

[0008] When the initial error and the real-time error meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop are cascaded adjusted.

[0009] When the initial error and the real-time error do not meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure is adjusted in a single loop.

[0010] In one embodiment, the cascade adjustment conditions include: the absolute value of the real-time error is less than or equal to the target temperature threshold, and the initial error is greater than a preset temperature difference.

[0011] In one embodiment, when the initial error and the implementation error do not meet the preset cascade adjustment conditions, the single-loop adjustment of the thermal compensation power of the heat-conducting structure includes:

[0012] When the absolute value of the real-time error is less than or equal to the target temperature threshold, and the initial error is less than or equal to the preset temperature difference, the thermal compensation power of the heat-conducting structure is adjusted according to the temperature value.

[0013] In one embodiment, the heat-conducting structure further includes a heating element connected to a heating adjustment switch. By controlling the on / off state of the heating adjustment switch, the heating duty cycle of the heating element is controlled, thereby adjusting the heat compensation power.

[0014] In one embodiment, controlling the on / off state of the heating regulating switch includes:

[0015] f2(t)=k p e(k)+k i T j +k d ;

[0016] Where f2(t) is the signal acting on the heating regulating switch, e(k) is the real-time error at the k-th sampling time, e(k-1) is the real-time error at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p For proportional gain, k i For integral gain, k d This is the differential gain.

[0017] In one embodiment, when the initial error and the implementation error do not meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure is adjusted in a single loop, further comprising:

[0018] When the real-time error exceeds the target temperature threshold, the heating element in the heat-conducting structure is adjusted to have its thermal compensation power fully on or off.

[0019] In one embodiment, the circulation loop includes a first circulation loop, which is provided with a first compressor, a condenser, a first throttle valve, and a flow channel, which are sequentially connected and closed. The heat-conducting structure is disposed between the flow channel and the chip under test. The cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop includes: cascade adjustment of the thermal compensation power of the heating element in the heat-conducting structure and the opening degree of the first throttle valve according to the temperature value.

[0020] In one embodiment, the thermal compensation power of the heating element in the heat-conducting structure and the opening degree of the first throttle valve are cascadedly adjusted according to the temperature value, including:

[0021] f3(t)=f2(t)+u(k)=(k p +k lp e(k)+T(k) i j+ k li j )+k d +k ld ;

[0022] Where f2(t) is the signal acting on the heating regulating switch, u(k) is the signal acting on the first throttle valve, e(k) and el(k) are the real-time errors at the k-th sampling time, e(k-1) and el(k-1) are the real-time errors at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p k lp For proportional gain, k i k li For integral gain, k d k ld This is the differential gain.

[0023] In one embodiment, the circulation loop further includes a second circulation loop, and the condenser in the first circulation loop is a condenser-evaporator; the second circulation loop is provided with a second compressor, a condenser, a second throttle valve and the condenser-evaporator, which are connected and closed in sequence, and the condenser-evaporator is used for heat exchange between the first circulation loop and the second circulation loop;

[0024] The cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the loop includes: cascade adjustment of the thermal compensation power of the heating element in the heat-conducting structure, as well as the opening degree of the first throttle valve and the second throttle valve, according to the temperature value.

[0025] In one embodiment, the thermal compensation power of the heating element in the heat-conducting structure and the opening degrees of the first and second throttle valves are cascaded and adjusted according to the temperature value, including:

[0026] f3(t)=f2(t)+u(k)1+u(k)2=(k p +k lp1+ klp2 e(k)+T(k) i j+ k li1 j+ k li2 j )+k d +k ld1 +k ld2 ;

[0027] Where f2(t) is the signal acting on the heating regulating switch, u(k)1 is the signal acting on the first throttle valve, u(k)2 is the signal acting on the second throttle valve, e(k) and el(k) are the real-time errors at the k-th sampling time, e(k-1) and el(k-1) are the real-time errors at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p k lp1 k lp2 For proportional gain, k i k li1 k li2 For integral gain, k d k ld1 k ld2 This is the differential gain.

[0028] A second aspect of this application provides an ATC system for chip testing, including a loop, a heat-conducting structure, and a host computer. The heat-conducting structure is disposed between the loop and the chip under test. The host computer is used for control according to the above method.

[0029] The aforementioned chip testing uses an ATC system and control method to acquire real-time temperature values ​​from the temperature acquisition unit in the heat-conducting structure. Combined with analysis of the set operating temperature, initial and real-time errors are obtained. Based on the analysis of initial and real-time errors, when the cascade adjustment conditions are met, the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop are cascaded. When the preset cascade adjustment conditions are not met, the thermal compensation power of the heat-conducting structure is adjusted in a single loop. Cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop when the initial and real-time errors meet the cascade adjustment conditions effectively solves the problem of large overshoot caused by excessive instantaneous power during chip testing, thus improving test reliability. Attached Figure Description

[0030] Figure 1This is a flowchart of an ATC system control method for chip testing in one embodiment;

[0031] Figure 2 This is a schematic diagram of the structure of an ATC system for chip testing in one embodiment;

[0032] Figure 3 This is a schematic diagram of the structure of an ATC system for chip testing in another embodiment. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0035] It is understood that the terms "first," "second," etc., used in this application may be used to describe various elements herein, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., transmit electrical signals or data to each other.

[0036] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0037] In one embodiment, such as Figure 1 As shown, an ATC system control method for chip testing is provided, including:

[0038] Step S110: Real-time acquisition of temperature values ​​collected by the temperature acquisition device in the heat-conducting structure.

[0039] The heat-conducting structure is positioned between the loop and the chip under test (DUT) in the ATC system used for chip testing. The heat-conducting structure can be a KIT (Knob-In-Test) structure, which has a stepped structure that fits onto the bottom surface of the flow channel in the loop. The upper part of the heat-conducting structure is in contact with the flow channel, while the lower part, the pressure head, presses against the chip, facilitating heat exchange between the DUT and the flow channel. The heat-conducting structure includes a heating element and a temperature sensor. The temperature sensor monitors the temperature TC at the bottom surface of the pressure head. The temperature signal output by the sensor is acquired by a temperature acquisition unit and then sent to the host computer. Assuming the loop remains stable, the host computer controls the heating duty cycle of the heating element based on the received temperature value, forming a closed-loop control system to maintain the temperature TC at the set operating temperature. In other embodiments, the heat-conducting structure can also be a test socket heat-conducting structure, a preheating plate heat-conducting structure, a feed shuttle heat-conducting structure, etc. The host computer can be, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices. Portable wearable devices can include smartwatches, smart bracelets, head-mounted devices, etc.

[0040] The circulation loop can consist of a single-stage loop or two-stage loops (a low-temperature stage loop and a high-temperature stage loop). When the temperature of the high-temperature stage loop or the plant water temperature is unstable, the cooling capacity provided by the system cooling water is very small. In this case, the problem of insufficient cooling capacity of the high-temperature stage must be considered in the overall temperature control. Therefore, by acquiring and analyzing the temperature values ​​detected in the heat-conducting structure in real time, the actual operating conditions can be analyzed to make targeted adjustments based on the actual operating conditions.

[0041] Step S120: Based on the temperature value and the set operating temperature, the initial error and real-time error are obtained through analysis.

[0042] The host computer acquires the temperature value in the heat-conducting structure in real time, and analyzes the initial error and real-time error based on the acquired temperature value and the set operating temperature TS. The difference between the acquired temperature value at the beginning of control and the set operating temperature TS is taken as the initial error T1, and the difference between the acquired temperature and the set operating temperature TS in each subsequent iteration is taken as the real-time error e.

[0043] Step S130: When the initial error and real-time error meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop are cascaded adjusted.

[0044] The specific details of the cascade adjustment conditions are not unique and can be set according to actual needs. In this embodiment, the cascade adjustment conditions include: the absolute value of the real-time error e is less than or equal to the target temperature threshold M, and the initial error T1 is greater than the preset temperature difference N. The values ​​of the target temperature threshold M and the preset temperature difference N are not unique. For example, based on the steady-state temperature fluctuation of the test chip, the target temperature threshold M can be set to 0.5℃, and the preset temperature difference N can be determined according to the chip's heat dissipation power and stability requirements, specifically set to 1℃.

[0045] If the initial error T1 and the real-time error e satisfy the cascade regulation condition, then the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop are cascadedly regulated. This can be achieved by adjusting the heating duty cycle of the heating element in the heat-conducting structure and adjusting the opening of the regulating valve in the circulation loop to control the refrigerant flow rate. The type of regulating valve is not unique; it can be an electronic expansion valve, a common electromagnetic opening valve, etc. When the circulation loop is a fluorinated liquid heat exchange loop, the regulating valve is used for opening regulation. When the circulation loop includes a refrigeration loop containing a compressor, condenser, evaporator, etc., the regulating valve is used as a throttling valve.

[0046] Step S140: When the initial error and real-time error do not meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure is adjusted in a single loop. When the initial error T1 and real-time error e do not meet the preset cascade adjustment conditions, only the thermal compensation power of the heat-conducting structure needs to be adjusted in a single loop, for example, by adjusting the heating duty cycle of the heating element in the heat-conducting structure separately.

[0047] The ATC system control method used in the above chip testing, when the initial error T1 and the real-time error e meet the cascade adjustment conditions, performs cascade adjustment on the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop. This can effectively solve the problem of large overshoot caused by excessive instantaneous power during chip testing and improve test reliability.

[0048] In one embodiment, the ATC system for chip testing further includes a driver module. The host computer is electrically connected to the heating element in the thermally conductive structure and the regulating valve in the circulation loop through the driver module. The host computer achieves coordinated control of the regulating valve and the heating element through cascade linkage. The cascade linkage includes hardware cascading or software cascading.

[0049] The hardware cascading (not shown in the figure) includes: the main control output of the host computer is electrically connected to the drive module; the first output of the drive module is electrically connected to the controlled end of the regulating valve; and the second output of the drive module is electrically connected to the setpoint of the heating element, so that the host computer outputs a main control signal to drive the regulating valve to adjust and outputs a secondary setpoint signal to drive the heating element to adjust; or, the main control output of the host computer is electrically connected to the drive module; the first output of the drive module is electrically connected to the controlled end of the heating element; and the second output of the drive module is electrically connected to the setpoint of the regulating valve, so that the host computer outputs a main control signal to drive the heating element to adjust and outputs a secondary setpoint signal to drive the regulating valve to adjust. Hardware cascading control can be achieved through either of these two methods.

[0050] Furthermore, such as Figure 2 As shown, the drive module includes a heating adjustment switch S1 and an opening adjustment switch S2; the software cascade includes:

[0051] The host computer is electrically connected to the regulating valve through the drive channel of the opening adjustment switch S2, and to the heating element through the drive channel of the heating adjustment switch S1. After receiving the temperature signal from the temperature acquisition unit, the host computer uses a software algorithm to use the PID control output of the regulating valve as the secondary setpoint or superposition term of the heating element, or vice versa. The heating adjustment switch S1 can be a solid-state relay or other type of switch, and the opening adjustment switch S2 can be a relay or other type of switch. Through software calculation and correlation, the cascade linkage of the thermal compensation power of the heat-conducting structure KIT and the refrigerant flow rate of the circulation loop is realized. It can also switch between single-loop regulation and cascade linkage regulation according to operating conditions.

[0052] In one embodiment, step S140 includes: adjusting the heat compensation power of the heating element in the heat-conducting structure to be fully on or fully off when the real-time error e is greater than the target temperature threshold M. When the real-time error e is greater than the target temperature threshold M, the system can realize the function of fully on or fully off the heat compensation power, that is, the heating element is coarsely adjusted at full power p, which can be expressed as:

[0053] .

[0054] In one embodiment, step S140 includes: adjusting the thermal compensation power of the heat-conducting structure according to the temperature value when the absolute value of the real-time error e is less than or equal to the target temperature threshold M and the initial error T1 is less than or equal to the preset temperature difference N.

[0055] When the absolute value of the real-time error e is less than or equal to the target temperature threshold M, and the initial error T1 is less than or equal to the preset temperature difference N, it indicates that when the actual temperature deviates from the target temperature but is within the threshold range, the ambient temperature is stable, and the system's evaporation temperature deviation is small, the fuzzy self-tuning PID controller system is activated for adjustment. The heat-conducting structure KIT also includes a heating element connected to the heating adjustment switch S1. By controlling the on / off state of the heating adjustment switch S1, the energization and de-energization of the heating element are changed, thereby controlling the heating duty cycle of the heating element and adjusting the thermal compensation power.

[0056] It is understandable that adjusting the heat compensation power by controlling the on / off state of the heating adjustment switch S1 is not a unique method. In the adjustment of the fuzzy self-tuning PID controller system, let the real-time error e, the error change rate ec, and Δk be... p Δk i and Δk d All parameters follow a triangular distribution. Based on the real-time temperature TC fed back by the temperature sensor, the values ​​of the error change rate ec and real-time error e at different times can be obtained, serving as the input variables for the fuzzy controller. The three parameters k of the PID controller are then adjusted based on the values ​​of the error change rate ec and real-time error e at different times. p k i k d Perform self-tuning. The tuning coefficients are calculated as follows:

[0057] k p =k p0 +Δk p ;

[0058] k i =k i0 +Δk i ;

[0059] k d =k d0 +Δk d ;

[0060] Where, k p0 k i0 k d0 Δk can be measured using the engineering tuning method. p Δk i Δk d They are k p k i k d The correction value.

[0061] In this embodiment, controlling the on / off state of the heating regulating switch S1 includes:

[0062] f2(t)=k p e(k)+k i T j +k d ;

[0063] Where f2(t) is the signal acting on the heating regulating switch S1, e(k) is the real-time error at the k-th sampling time, e(k-1) is the real-time error at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p The proportional gain determines the strength of the response to the current error, k. i The integral gain is used to eliminate steady-state error (static error) by correcting the output through the accumulation of historical errors. d As the differential gain, it is adjusted according to the trend of error change (derivative), which can predict future errors and suppress overshoot in advance, thereby improving system stability.

[0064] By adjusting the fuzzy self-tuning PID controller system, the refrigerant evaporation temperature can be adaptively adjusted, enabling the system to achieve a stable and rapid response. This ensures that the actual temperature during steady-state chip testing is always kept within the required range, solving the problem of unstable control point temperature caused by frequent changes in the duty cycle of the thermal compensation heating element.

[0065] When the absolute value of the real-time error e is less than or equal to the target temperature threshold M, and the initial error T1 is greater than the preset temperature difference N, it indicates that the chip's instantaneous power is extremely high. The change in the chip's power causes the heating amount to exceed the threshold, and the cascade control adjustment based on fuzzy self-tuning PID is enabled. That is, in the adjustment of the fuzzy self-tuning PID1 controller system, a PID2 control that increases the control of the refrigerant flow is connected in series, and the opening of the regulating valve in the circulation loop is quickly adjusted.

[0066] Specifically, the circulation loop includes a first circulation loop, which is equipped with a first compressor, a condenser, a first throttle valve, and a flow channel, which are sequentially connected and closed. A heat-conducting structure KIT is positioned between the flow channel and the chip under test. For example... Figure 2 As shown, when the first circulation loop is used as the low-temperature stage circulation loop, the first compressor is a low-temperature stage compressor, and the first throttling valve K1 is a low-temperature stage throttling valve, which can be an electronic expansion valve. The discrete PID formula for refrigerant flow control is as follows:

[0067] u(k)=k lp e(k)+k li T j +k ld ;

[0068] u(k) is the signal acting on the first throttle valve K1, el(k) is the real-time error at the k-th sampling time, el(k-1) is the real-time error at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j This represents the error at any sampling time j between the initial time and the current sampling time (k). lp For proportional gain, k li For integral gain, k ld For differential gain, the tuning methods of the three are the same as k. p k i k d Similarly, I will not go into details here.

[0069] In this embodiment, step S130 involves cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop, including: cascade adjustment of the thermal compensation power of the heating element in the heat-conducting structure and the first throttling valve degree based on the temperature value, specifically:

[0070] f3(t)=f2(t)+u(k)=(k p +k lp e(k)+T(k) i j+ k li j )+k d +k ld ;

[0071] Where f2(t) is the signal acting on the heating regulating switch, u(k) is the signal acting on the first throttle valve, e(k) and el(k) are the real-time errors at the k-th sampling time, e(k-1) and el(k-1) are the real-time errors at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p k lp For proportional gain, k i k li For integral gain, k d k ld This is the differential gain.

[0072] In one embodiment, the circulation loop further includes a second circulation loop, and the condenser in the first circulation loop is a condenser-evaporator; the second circulation loop is provided with a second compressor, a condenser, a second throttle valve, and a condenser-evaporator, which are sequentially connected and closed, and the condenser-evaporator is used for heat exchange between the first circulation loop and the second circulation loop. Figure 3As shown, when the second circulation loop is used as a high-temperature stage circulation loop, the second compressor is a high-temperature stage compressor, and the second throttle valve K2 is used as a high-temperature stage throttle valve, specifically an electronic expansion valve. The condenser in the second circulation loop can be a water-cooled condenser, connected to the plant water supply for heat exchange with the second circulation loop. The host computer connects to the first throttle valve K1 via the opening adjustment switch S2 and to the second throttle valve K2 via the opening adjustment switch S3.

[0073] When the refrigeration loop includes both a low-temperature stage refrigeration loop and a high-temperature stage refrigeration loop, it constitutes a cascade compression refrigeration loop. Cascade control based on fuzzy self-tuning PID is achieved by simultaneously controlling the high-temperature stage throttling valve and the low-temperature stage throttling valve of the cascade compression refrigeration loop.

[0074] The discrete PID formula for low-temperature refrigerant flow control is as follows:

[0075] u(k)1=k lp1 e(k)1+k li1 T j +k ld1 ;

[0076] Where u(k)1 is the signal acting on the first throttle valve K1, el(k) is the real-time error at the k-th sampling time, el(k-1) is the real-time error at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j This represents the error at any sampling time j between the initial time and the current sampling time (k). lp1 For proportional gain, k li1 For integral gain, k ld1 For differential gain, the tuning methods of the three are the same as k. p k i k d Similarly, I will not go into details here.

[0077] The discrete PID formula for high-temperature refrigerant flow control is as follows:

[0078] u(k)2=k lp2 e(k)2+k li2 T j +k ld2 ;

[0079] Where u(k)2 is the signal acting on the second throttle valve K2, el(k) is the real-time error at the k-th sampling time, el(k-1) is the real-time error at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e jThis represents the error at any sampling time j between the initial time and the current sampling time (k). lp2 For proportional gain, k li2 For integral gain, k ld2 For differential gain, the tuning methods of the three are the same as k. p k i k d Similarly, I will not go into details here.

[0080] In this embodiment, step S130 involves cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the loop, including: cascade adjustment of the thermal compensation power of the heating element in the heat-conducting structure, and the opening degrees of the first throttle valve K1 and the second throttle valve K2, based on the temperature value. Specifically:

[0081] f3(t)=f2(t)+u(k)1+u(k)2=(k p +k lp1+ k lp2 e(k)+T(k) i j+ k li1 j+ k li2 j )+k d +k ld1 +k ld2 ;

[0082] Where f2(t) is the signal acting on the heating regulating switch S1, u(k)1 is the signal acting on the first throttle valve K1, u(k)2 is the signal acting on the second throttle valve K2, e(k) and el(k) are the real-time errors at the k-th sampling time, e(k-1) and el(k-1) are the real-time errors at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p k lp1 k lp2 For proportional gain, k i k li1 k li2 For integral gain, k d k ld1 k ld2 This is the differential gain.

[0083] In this embodiment, when the absolute value of the real-time error e is less than or equal to the target temperature threshold M, and the initial error T1 is greater than the preset temperature difference N, it indicates that the chip's instantaneous power is extremely high, and the change in the chip's power causes the heating amount to exceed the threshold excessively. When increasing the PID control of the refrigerant flow rate in one series loop is insufficient, the opening of the PID control of the refrigerant flow rate is increased by connecting the high-temperature stage and the low-temperature stage loops in series to solve the problem of large overshoot caused by excessive instantaneous power during chip testing. It can be understood that in other embodiments, more refrigerant flow control valves (such as a third throttle valve, a fourth throttle valve, etc.) can be incorporated into the cascade control based on fuzzy self-tuning PID.

[0084] The aforementioned ATC system control method for chip testing employs a PID control logic that determines the target temperature threshold M and the preset temperature difference N. Based on different determination results, it uses full power p for coarse adjustment, fuzzy self-tuning PID controller system adjustment, or cascade control adjustment based on fuzzy self-tuning PID. When the absolute value of the real-time error e is less than or equal to the target temperature threshold M, and the initial error T1 is greater than the preset temperature difference N, it indicates that the chip's instantaneous power is extremely high. In this case, cascade control adjustment based on fuzzy self-tuning PID is used. This is achieved by compensating for the heating element's PID, and then adding a PID control loop (low-temperature stage throttle valve) in series to increase the refrigerant flow, or adding two PID control loops (high-temperature stage throttle valve and low-temperature stage throttle valve) in series to increase the refrigerant flow, or adding multiple PID control loops in series to increase the refrigerant flow. This addresses the problem of excessive overshoot caused by excessive instantaneous power during chip testing.

[0085] In one embodiment, such as Figure 2 and Figure 3 As shown, an ATC system for chip testing is also provided, including a loop, a thermally conductive structure KIT, and a host computer. The thermally conductive structure KIT is disposed between the loop and the chip under test. The host computer is used for control according to the above method. It is understood that specific embodiments of the ATC system for chip testing have been described in detail in the above-described control method for the ATC system for chip testing, and will not be repeated here.

[0086] In addition, the ATC system for chip testing may also include a pressure gauge and / or a temperature gauge installed in the circulation loop and connected to a host computer. In this embodiment, the pressure gauge and temperature gauge are installed on the pipeline between the flow channel in the low-temperature stage circulation loop and the low-temperature stage compressor. The temperature signal output by the temperature gauge is acquired by a corresponding temperature acquisition device and the temperature value is output to the host computer. By using the pressure gauge and temperature gauge to perform pressure detection and temperature detection respectively, the system monitors whether the refrigerant pressure and temperature in the circulation loop meet the requirements.

[0087] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0088] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A control method for an ATC system used for chip testing, characterized in that, include: Real-time acquisition of temperature values ​​collected by the temperature acquisition device in the heat-conducting structure; The heat-conducting structure is disposed between the circulation loop and the chip under test in the chip testing ATC system. The initial error and real-time error are obtained based on the temperature value and the set operating temperature. When the initial error and the real-time error meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop are cascaded adjusted. When the initial error and the real-time error do not meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure is adjusted in a single loop.

2. The method according to claim 1, characterized in that, The cascade adjustment conditions include: the absolute value of the real-time error is less than or equal to the target temperature threshold, and the initial error is greater than the preset temperature difference.

3. The method according to claim 2, characterized in that, When the initial error and the implementation error do not meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure is adjusted in a single loop, including: When the absolute value of the real-time error is less than or equal to the target temperature threshold, and the initial error is less than or equal to the preset temperature difference, the thermal compensation power of the heat-conducting structure is adjusted according to the temperature value.

4. The method according to claim 3, characterized in that, The heat-conducting structure also includes a heating element connected to a heating adjustment switch. By controlling the on / off state of the heating adjustment switch, the heating duty cycle of the heating element is controlled, thereby adjusting the heat compensation power.

5. The method according to claim 4, characterized in that, Controlling the on / off state of the heating regulating switch includes: ； Wherein, f2(t) is the signal acting on the heating regulating switch, e(k) is the real-time error at the kth sampling moment, e(k-1) is the real-time error at the (k-1)th sampling moment, T is the temperature value collected by the temperature collector, e j Error at any sampling moment j between the initial moment and the current sampling moment (k) is represented as e(k) p The proportional gain is k i The integral gain is k d The differential gain is k 6. The method according to claim 3, characterized in that, When the initial error and the implementation error do not meet the preset cascade adjustment conditions, the thermal compensation power of the heat-conducting structure is adjusted in a single loop, which further includes: When the real-time error exceeds the target temperature threshold, the heating element in the heat-conducting structure is adjusted to have its thermal compensation power fully on or off.

7. The method according to any one of claims 1 to 6, characterized in that, The circulation loop includes a first circulation loop, which is provided with a first compressor, a condenser, a first throttle valve and a flow channel, which are connected and closed in sequence. The heat-conducting structure is disposed between the flow channel and the chip under test. The cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the circulation loop includes: cascade adjustment of the thermal compensation power of the heating element in the heat-conducting structure and the opening degree of the first throttle valve according to the temperature value.

8. The method according to claim 7, characterized in that, The thermal compensation power of the heating element in the heat-conducting structure and the opening degree of the first throttle valve are cascadedly adjusted according to the temperature value, including: ； Where f2(t) is the signal acting on the heating regulating switch, u(k) is the signal acting on the first throttle valve, e(k) and el(k) are the real-time errors at the k-th sampling time, e(k-1) and el(k-1) are the real-time errors at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p k lp For proportional gain, k i k li For integral gain, k d k ld This is the differential gain.

9. The method according to claim 7, characterized in that, The circulation loop also includes a second circulation loop. The condenser in the first circulation loop is a condenser-evaporator. The second circulation loop is provided with a second compressor, a condenser, a second throttle valve and the condenser-evaporator, which are connected and closed in sequence. The condenser-evaporator is used for heat exchange between the first circulation loop and the second circulation loop. The cascade adjustment of the thermal compensation power of the heat-conducting structure and the refrigerant flow rate of the loop includes: cascade adjustment of the thermal compensation power of the heating element in the heat-conducting structure, as well as the opening degree of the first throttle valve and the second throttle valve, according to the temperature value.

10. The method according to claim 9, characterized in that, The thermal compensation power of the heating element in the heat-conducting structure, based on the temperature value, and the cascade adjustment of the opening degrees of the first and second throttle valves, include: ； Where f2(t) is the signal acting on the heating regulating switch, u(k)1 is the signal acting on the first throttle valve, u(k)2 is the signal acting on the second throttle valve, e(k) and el(k) are the real-time errors at the k-th sampling time, e(k-1) and el(k-1) are the real-time errors at the (k-1)-th sampling time, T is the temperature value collected by the temperature acquisition device, and e j Let k represent the error at any sampling time j between the initial time and the current sampling time (k). p k lp1 k lp2 For proportional gain, k i k li1 k li2 For integral gain, k d k ld1 k ld2 This is the differential gain.

11. An ATC system for chip testing, characterized in that, It includes a circulation loop, a heat-conducting structure, and a host computer, wherein the heat-conducting structure is disposed between the circulation loop and the chip under test; the host computer is used for control according to any one of claims 1 to 10.

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