Temperature control method for inspection system, and inspection system

Abstract

Provided are a temperature control method for an inspection system and an inspection system, the inspection system inspecting a substrate while performing temperature control by suppressing overshoot of a junction temperature of an electronic device.　The temperature control method is for an inspection system comprising a chuck that holds a substrate having an electronic device to be inspected, and a tester that applies inspection power to the electronic device to inspect the electronic device. The method comprises: a step for obtaining a model of a first transfer function of a temperature rise of the electronic device from heat generation due to application of the inspection power to the electronic device; a step for obtaining a model of a second transfer function of the temperature of the chuck when a set temperature of the chuck is changed; a step for acquiring an inspection timing of the electronic device from the tester; and a step for starting temperature control of the chuck on the basis of the first transfer function and the second transfer function prior to the start of inspection of the electronic device.

Description

Temperature control method for inspection system and inspection system

[0001] The present disclosure relates to a temperature control method for an inspection system and an inspection system.

[0002] Patent Document 1 discloses a control method for an inspection device that includes a chuck for placing an object under test, a tester that supplies power to the object under test to inspect the object under test, and a control unit that controls the temperature of the chuck, and when it is not possible to provide feedback of the actual temperature of the object under test, the control method estimates a temperature difference between the temperature of the chuck and the temperature of the object under test based on the amount of heat generated by the object under test, corrects the target temperature of the chuck based on the target temperature of the object under test and the temperature difference, and controls the temperature of the chuck based on the corrected target temperature of the chuck and the actual temperature of the chuck.

[0003] Japanese Patent Application Laid-Open No. 2022-90538

[0004] In one aspect, the present disclosure provides a temperature control method and an inspection system for an inspection system that inspects a substrate while performing temperature control by suppressing overshoot of a junction temperature of an electronic device.

[0005] In order to solve the above problem, according to one aspect, there is provided a temperature control method for an inspection system including a chuck that holds a substrate having an electronic device to be inspected and a tester that applies inspection power to the electronic device to inspect the electronic device, the temperature control method including: a step of modeling and determining a first transfer function of a temperature rise of the electronic device from heat generated by applying the inspection power to the electronic device; a step of modeling and determining a second transfer function of the temperature of the chuck when the set temperature of the chuck is changed; a step of acquiring inspection timing of the electronic device from the tester; and a step of starting temperature control of the chuck based on the first transfer function and the second transfer function before inspection of the electronic device begins.

[0006] According to one aspect, it is possible to provide a temperature control method and an inspection system for an inspection system that inspects a substrate while performing temperature control by suppressing overshoot of the junction temperature of an electronic device.

[0007] An example of a perspective view of an inspection system. An example of a configuration diagram of an inspection system. An example of a plan view schematically showing the configuration of a substrate. An example of an enlarged view of an inspection system enlarging the vicinity of an electronic device. An example of a diagram showing a heat flow model. An example of a block diagram explaining state estimation using an observer. An example of a block diagram explaining state feedback. A diagram showing models of the stage temperature and the junction temperature of an electronic device. A flowchart explaining an example of a method for controlling the junction temperature of an electronic device. A graph showing an example of temperature control of the stage temperature and the junction temperature of an electronic device.

[0008] Various exemplary embodiments will be described in detail below with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0009] An inspection system 1, which is an example of an inspection system according to this embodiment, will be described with reference to Fig. 1. Fig. 1 is an example of a perspective view of the inspection system 1. Fig. 2 is an example of a configuration diagram of the inspection system 1. Note that Fig. 2 shows a schematic view of components built into the inspection system 1 as a partial cross-sectional view.

[0010] In a semiconductor manufacturing process, a large number of electronic devices D (see FIG. 3 described later; also referred to as dies) having a predetermined circuit pattern are formed on a substrate W such as a semiconductor wafer. The formed electronic devices D are inspected for electrical characteristics and sorted into good and bad products. The inspection of the electronic devices D is performed, for example, using an inspection system 1 while the substrate W is in the state before the individual electronic devices D are separated.

[0011] The inspection system 1 performs temperature control while inspecting the electrical characteristics of a plurality of electronic devices D (see FIG. 3 described later) formed on a substrate W. That is, the inspection system 1 supplies inspection power to the electronic devices D when the electronic devices D are at or above a predetermined inspection temperature, and inspects the electrical characteristics and the like at that time.

[0012] The inspection system 1 includes a storage chamber 2 , a loader 3 , and a tester 4 .

[0013] The storage chamber 2 has a hollow housing 11. Inside the housing 11, the storage chamber 2 has a stage (also referred to as a "chuck") 10 on which the substrate W is placed. The stage 10 has a suction holder (not shown) that suction-holds the substrate W so that the relative position of the substrate W with respect to the stage 10 does not shift. The storage chamber 2 also has a movement mechanism (not shown) inside the housing 11 that moves the stage 10 horizontally and vertically. This movement mechanism adjusts the relative positions of a probe card 12 (described later) and the substrate W, so that desired electrode portions E (see FIG. 3 described later) on the surface of the substrate W can be brought into contact with probes 12a of the probe card 12.

[0014] The accommodation chamber 2 has a probe card 12 inside a housing 11. The probe card 12 is arranged above the stage 10 so as to face the stage 10. The probe card 12 has a plurality of needle-shaped probes 12a arranged corresponding to electrode pads or solder bumps provided corresponding to electrode portions E of each electronic device D on the substrate W. The probe card 12 is connected to the tester 4 via an interface 13. When testing electrical characteristics, each probe 12a comes into contact with the electrode portion E of each electronic device D on the substrate W, supplies power from the tester 4 to the electronic device D via the interface 13, and transmits signals from the electronic device D to the tester 4 via the interface 13.

[0015] The loader 3 is provided with a FOUP (Front Opening Unify Pod), which is a transport container that accommodates substrates W. The loader 3 also has a transport mechanism (not shown) that transports the substrates W. The transport mechanism removes the substrates W accommodated in the FOUP and transports them to a stage 10 in the accommodation chamber 2. The transport mechanism also receives the substrates W from the stage 10 after the inspection of the electrical characteristics of the electronic devices D has been completed, and accommodates them in the FOUP.

[0016] The tester 4 has a test board (not shown) that reproduces part of the circuit configuration of a motherboard on which the electronic device D is mounted. The test board of the tester 4 is connected to a tester computer 15 that judges the quality of the electronic device D based on signals from the electronic device D. The tester 4 can reproduce the circuit configurations of multiple types of motherboards by changing the test board. The probe card 12 is provided with multiple probes 12a, which are brought into contact with multiple electrode portions E of the electronic device D, respectively. The tester 4 also has multiple detection means for detecting electrical characteristics of the electronic device D. This allows the tester 4 to detect multiple electrical characteristics of the electronic device D.

[0017] The inspection system 1 also includes a user interface unit 16 for displaying information to a user and for the user to input instructions. The user interface unit 16 includes, for example, an input unit such as a touch panel or a keyboard, and a display unit such as a liquid crystal display.

[0018] As described above, the inspection system 1 includes the stage 10 as a substrate holding unit that holds the substrate W. The inspection system 1 also includes a probe card 12 having probes 12 a, an interface 13, and a tester 4 as a detection unit that detects electrical characteristics of the electronic device D by supplying inspection power to the electrode unit E of the electronic device D provided on the substrate W.

[0019] Furthermore, the loader 3 has a temperature control unit 14. The temperature control unit 14 has a power supply 25, a chiller 26, a power supply 55, and a control unit 90.

[0020] The stage 10 is provided with a heater 20 (heating unit) that heats the stage 10. A power supply 25 supplies power to the heater 20 provided on the stage 10. A coolant flow path 10a through which a heat transfer medium (such as antifreeze) flows is formed inside the stage 10. The chiller 26 circulates the temperature-controlled heat transfer medium through the coolant flow path 10a. As described above, the inspection system 1 includes the heater 20, the power supply 25, the coolant flow path 10a, and the chiller 26 as a holder temperature adjustment mechanism that adjusts the temperature of the substrate holder. Note that the configuration of the holder temperature adjustment mechanism is not limited thereto. Note that, although the heater 20 has been described as the heating unit that heats the stage 10, the present invention is not limited thereto. The heating unit that heats the stage 10 may also be a light source such as an LED that irradiates light onto the stage 10 on which the substrate W is placed, thereby heating the stage 10.

[0021] The holder temperature adjustment mechanism also includes a temperature detection unit 30 that detects the temperature of the substrate holder. The temperature detection unit 30 is provided on the stage 10 and detects the temperature Tchuck of the stage 10. The temperature Tchuck of the stage 10 detected by the temperature detection unit 30 is input to the control unit 90. While the temperature detection unit 30 is illustrated as being a single unit, this is not limited to this, and it is preferable to provide multiple temperature detection units 30 on the stage 10 for the electronic devices D that are supplied with power and generate heat. It is also preferable to switch the temperature detection unit 30 that detects the temperature Tchuck when switching the electronic devices D that are supplied with power and generate heat. It is also preferable to detect the temperature Tchuck based on a model that includes multiple temperature detection units 30.

[0022] The tester 4 is also provided with a temperature adjustment mechanism 50 that adjusts the temperature of the probe card 12. The temperature adjustment mechanism 50 may include a heater (not shown) that heats the probe card 12, a cooling fan (not shown) that cools the probe card 12, and the like. The power supply 55 supplies power to the temperature adjustment mechanism 50 provided in the tester 4. In this way, the inspection system 1 includes the temperature adjustment mechanism 50 as a detection unit temperature adjustment mechanism that adjusts the temperature of the detection unit. However, the configuration of the detection unit temperature adjustment mechanism is not limited to this. The detection unit temperature adjustment mechanism may also include a configuration that adjusts the temperature of the detection unit by liquid cooling.

[0023] The detection unit temperature adjustment mechanism also includes a temperature detection unit 60 that detects the temperature of the detection unit. The temperature detection unit 60 is provided on the probe card 12 and detects the temperature Tprob of the probe card 12. The temperature Tprob of the probe card 12 detected by the temperature detection unit 60 is input to the control unit 90. While the temperature detection unit 60 has been described as being provided on the probe card 12, this is not limiting and the temperature detection unit may be a temperature detection unit capable of detecting a temperature representative of the temperature of the probe. For example, the temperature detection unit 60 may be a temperature detection unit that detects the temperature of the probe 12a. While the temperature detection unit 60 is illustrated as being a single unit, this is not limiting and it is preferable to provide multiple temperature detection units 60 on the probe card 12 for the electronic devices D that are supplied with power and generate heat. Furthermore, when switching the electronic devices D that are supplied with power and generate heat, it is preferable to also switch the temperature detection unit 60 that detects the temperature Tprob. Furthermore, it is preferable to detect the temperature Tprob based on a model including multiple temperature detection units 60.

[0024] The tester 4 also has a power detection unit 41 that detects the test power (current and voltage) supplied from the tester 4 to the electronic device D via the interface 13 and the probe card 12. The test power detected by the power detection unit 41 is input to the control unit 90.

[0025] The control unit 90 has a holding unit temperature control unit 91, a detection unit temperature control unit 92, and an analysis unit 93. The control unit 90 controls the holding unit temperature adjustment mechanism and the detection unit temperature adjustment mechanism so that the junction temperature Tj (temperature of the substrate W) of the electronic device D becomes the inspection temperature. The control unit 90 also controls the holding unit temperature adjustment mechanism and the detection unit temperature adjustment mechanism so that the temperature difference between the substrate W and the probe card 12 is within a predetermined threshold value.

[0026] The holder temperature control unit 91 controls the holder temperature adjustment mechanism so that the temperature Tchuck of the substrate holder detected by the temperature detection unit 30 becomes the target temperature. While the illustrated embodiment illustrates a single temperature detection unit 30, this is not limiting. It is preferable to provide multiple temperature detection units 30 on the stage 10 for the electronic devices D that are supplied with power and generate heat. Furthermore, when switching between electronic devices D that are supplied with power and generate heat, it is also preferable to switch the temperature detection unit 30 that detects the temperature Tchuck. It is also preferable to detect the temperature Tchuck based on a model including multiple temperature detection units 30. That is, the holder temperature control unit 91 controls the power supply 25 to control the heat output of the heater 20, thereby controlling the temperature Tchuck of the stage 10. The holder temperature control unit 91 may also control the chiller 26 to control the temperature of the heat transfer medium supplied by the chiller 26 to the refrigerant flow path 10a, thereby controlling the temperature Tchuck of the stage 10.

[0027] The detection unit temperature control unit 92 controls the detection unit temperature adjustment mechanism so that the temperature Tprob detected by the temperature detection unit 60 becomes the target temperature. That is, the detection unit temperature control unit 92 controls the temperature adjustment mechanism 50 by controlling the power supply 55, thereby controlling the temperature Tprob of the probe card 12. Note that, although the temperature detection unit 60 is illustrated as being a single unit, this is not limitative, and it is preferable to provide a plurality of temperature detection units 60 on the probe card 12 for the electronic devices D that are supplied with power and generate heat. Furthermore, when switching the electronic devices D that are supplied with power and generate heat, it is preferable to also switch the temperature detection unit 60 that detects the temperature Tprob. Furthermore, it is preferable to detect the temperature Tprob based on a model including a plurality of temperature detection units 60.

[0028] The analysis unit 93 estimates the junction temperature Tj (temperature of the substrate W) of the electronic device D based on a heat flow model shown in FIG. 5 (described later). The control unit 90 then adjusts the chuck heat flux (see heat flow Ic described later with reference to FIG. 5 ) so that the target temperature Tchuck (holding unit target temperature) is reached. The control unit 90 may also be configured to adjust the chuck heat flux (see heat flow Ic described later with reference to FIG. 5 ) so that the target temperature Tchuck (holding unit target temperature) is reached, and adjust the probe heat flux (see heat flow Ip described later with reference to FIG. 5 ) so that the target temperature Tprob (detection unit target temperature) is reached. The holding unit temperature control unit 91 controls the holding unit temperature adjustment mechanism based on the holding unit target temperature calculated by the analysis unit 93. The detection unit temperature control unit 92 controls the detection unit temperature adjustment mechanism based on the detection unit target temperature calculated by the analysis unit 93. The holding unit target temperature and detection unit target temperature calculated by the analysis unit 93 can have multiple solutions. In reality, about 40% of the heat also escapes from the electronic device D to the probe card 12. The amount of heat absorbed from the electronic device D to the probe card 12 is in a trade-off relationship with the difference in thermal expansion between the probe card 12 and the substrate W. The amount of heat absorbed from the electronic device D to the probe card 12 is calculated as the amount of heat absorbed when the probes 12a fall within the range of the bonding pads (electrode portions E).

[0029] Next, the substrate W inspected in the above-described inspection system 1 will be described with reference to Fig. 3. Fig. 3 is a plan view schematically showing the configuration of the substrate W.

[0030] 3, a plurality of electronic devices D are formed on the surface of the substrate W at predetermined intervals by etching and wiring a substantially disk-shaped silicon substrate. Electrode portions E are formed on the surface of the electronic devices D, i.e., the substrate W, and the electrode portions E are electrically connected to circuit elements inside the electronic devices D. By applying a voltage to the electrode portions E, a current can be passed through the circuit elements inside each electronic device D.

[0031] FIG. 4 is an example of an enlarged view of the inspection system 1, showing the electronic device D and its vicinity.

[0032] When the electrical characteristics and the like of the electronic device D are inspected, the substrate W is held on the stage 10. That is, the electronic device D is thermally connected to the stage 10. Furthermore, when the electrical characteristics and the like of the electronic device D are inspected, the probes 12a are in contact with the electrode portions E of the electronic device D. That is, the electronic device D is thermally connected to the probe card 12 via the probes 12a. Furthermore, the probe card 12 is in contact with the interface 13, and the interface 13 is in contact with the tester 4. That is, the probe card 12 is thermally connected to the tester 4 via the interface 13, and the tester 4 is thermally connected to the electronic device D via the probe card 12.

[0033] The temperature Tchuck of the stage 10 is detected by the temperature detection unit 30. The temperature Tprob of the probe card 12 is detected by the temperature detection unit 60.

[0034] Here, by passing a current through a PN junction (e.g., a transistor) formed in the electronic device D, it is possible to detect the junction temperature Tj of the electronic device D from the correlation between the generated electromotive force and temperature. However, when inspecting an electronic device D such as a logic IC, under conditions where a clock is generated, it may not be possible to properly detect the junction temperature Tj due to the influence of noise, etc.

[0035] Furthermore, when the electronic device D is inspected, a temperature difference occurs between the temperature Tchuck of the stage 10 and the junction temperature Tj of the electronic device D due to the thermal resistance between the stage 10 and the substrate W (electronic device D). For this reason, when the electronic device D is inspected by controlling the temperature so that the temperature Tchuck of the stage 10 is equal to the inspection temperature, the junction temperature Tj of the electronic device D may become higher than the inspection temperature. In other words, the electronic device D is inspected at a temperature higher than the inspection temperature, which may reduce the yield of the electronic device D.

[0036] Furthermore, when the electronic device D is inspected by controlling the temperature so that the temperature Tchuck of the stage 10 becomes the inspection temperature, the heat flow from the electronic device D to the detection unit becomes a disturbance.

[0037] The substrate W is mainly made of, for example, silicon. The probe card 12 is mainly made of, for example, glass epoxy. A temperature difference between the substrate W and the probe card 12 causes a difference in thermal expansion, which may cause the probes 12 a to come off the electrode portions E.

[0038] Next, a description will be given of temperature control in the inspection system 1 according to this embodiment. Fig. 5 is a diagram showing an example of a heat flow model.

[0039] 5 shows the heat flow Id of the electronic device D, the thermal resistance Rd of the electronic device D, the heat capacity Cd of the electronic device D, and the junction temperature Tj of the electronic device D. Also shown are the heat flow Ip of the probe card 12, the thermal resistance Rp of the probe card 12, the heat capacity Cp of the probe card 12, the temperature of the probe card 12 (probe card temperature) Tprob, the heat flow Idp from the probe card 12 to the electronic device D, and the thermal resistance Rdp from the probe card 12 to the electronic device D. Also shown are the heat flow Ic of the stage 10, the thermal resistance Rc of the stage 10, the heat capacity Cc of the stage 10, the temperature (chuck temperature) Tchuck of the stage 10, the heat flow Idc from the stage 10 to the electronic device D, and the thermal resistance Rdc from the stage 10 to the electronic device D. In Figure 5, the temperature detection unit 30 (see Figures 2 and 4) that detects the temperature Tchuck is described as being single, but performance can be further improved by arranging and switching between multiple temperature detection units 30 or by detecting the temperature Tchuck based on a model that includes multiple temperature detection units 30.

[0040] Here, the various thermal resistances and heat capacities are values ​​(obtainable values) that are determined in advance depending on the configuration of the substrate holder, the substrate W, and the detector, etc.

[0041] The heat flow Id of the electronic device D corresponds to the heat flow due to the test power detected by the power detection unit 41. The heat flow Ic of the stage 10 corresponds to the heat flow in the holder temperature adjustment mechanism. The heat flow Ip of the probe card 12 corresponds to the heat flow in the detection temperature adjustment mechanism. That is, the heat flows Id, Ic, and Ip are values ​​that can be detected by the control unit 90.

[0042] Furthermore, the temperature of the stage 10 (chuck temperature) Tchuck corresponds to the temperature detected by the temperature detection unit 30. The temperature of the probe card 12 (probe card temperature) Tprob corresponds to the temperature detected by the temperature detection unit 60. In other words, the temperatures Tchuck and Tprob are values ​​that can be detected by the control unit 90.

[0043] On the other hand, the junction temperature Tj of the electronic device D is a temperature that the control unit 90 cannot directly measure.

[0044] In the heat flow model shown in FIG. 5, the differential value of the junction temperature Tj (Tj dot), the differential value of the temperature Tprob of the probe card 12 (Tprob dot), and the differential value of the temperature Tchuck of the stage 10 (Tchuck dot) can be expressed by the following equations.

[0045]

[0046] Here, X １ = Tj, X ２ =Tchuck, X ３ = Tprob, U １ = id, U ２ = ic, U ３ = ip, it can be expressed by the following equation.

[0047]

[0048] That is, the above equations are expressed as dx / dt=Ax(t)+Bu(t) and y(t)=Cx(t).

[0049] FIG. 6 is an example of a block diagram illustrating state estimation using an observer. Block diagram 600 includes a controlled object 610 and an observer 620. Control object 610 corresponds to the above equation. Here, x(t) is an immeasurable value. By using observer 620, an estimated value of x(t) can be calculated (in FIG. 6, the estimated value of observer 620 is marked with a hat "^").

[0050] That is, the analysis unit 93 can estimate the junction temperature Tj of the electronic device D, which cannot be measured directly, by using the observer 620 shown in FIG. 6 in the heat flow model shown in FIG.

[0051] 7 is an example of a block diagram illustrating state feedback. Block diagram 700 includes an integral controller 710, an operator 720, a controlled object 730, an operator 740, and an operator 750. Although not shown, controlled object 730 shown in FIG. 7 includes an observer, similar to block diagram 600 shown in FIG. 6. An estimated value of x(t) estimated by the observer is input to integral controller 710 and operator 740.

[0052] The integral controller 710 performs state feedback of the estimated value of x(t) estimated by the observer.

[0053] Here, the X estimated by the observer １ The estimated value of (X １ hat) to Y １ That is, Y １ is the junction temperature Tj estimated by the observer. １ The estimated value of (X １ hat) and X ３ The difference between ２ That is, Y ２ is the difference between the junction temperature Tj estimated by the observer and the temperature Tprob, and is an estimated value of the temperature difference between the substrate W (electronic device D) and the probe card 12. These can be expressed by the following equations.

[0054]

[0055] Operator 740 calculates Y ｍ The estimated value of (Y ｍ hat) is fed back to operator 750.

[0056] This provides feedback regarding the junction temperature Tj and the difference between the junction temperature Tj and the temperature Tprob.

[0057] The integral controller 710 is ２ Y １ It is preferably configured to be faster than

[0058] As described above, the control unit 90 inspects the substrate W while adjusting the temperature control performed by the holder temperature adjustment mechanism and the detector temperature adjustment mechanism.

[0059] Specifically, the control unit 90 acquires and comprehensively analyzes the heat flow (Id) due to the inspection power output when the inspection power is supplied, the heat flow (Ic) in the holder temperature adjustment mechanism, and the heat flow (Ip) in the detector temperature adjustment mechanism, thereby enabling inspection of the substrate W while adjusting the temperature (junction temperature Tj) of the substrate W. This allows the electronic devices D to be at the inspection temperature when inspecting the electronic devices D, enabling the inspection to be performed favorably. Furthermore, a decrease in the yield of the electronic devices D can be prevented.

[0060] Furthermore, the control unit 90 acquires and comprehensively analyzes the heat flow (Id) due to the inspection power output when the inspection power is supplied, the heat flow (Ic) in the holder temperature adjustment mechanism, and the heat flow (Ip) in the detection unit temperature adjustment mechanism, thereby enabling inspection of the substrate W while adjusting the temperature difference between the temperature of the substrate W (junction temperature Tj) and the temperature of the detection unit (temperature Tprob). This reduces the difference in thermal expansion between the substrate W and the probe card 12, preventing the probes 12a from coming off the electrode portions E. Furthermore, friction between the probes 12a and the electrode portions E can be minimized.

[0061] Furthermore, the analysis unit 93 of the control unit 90 can estimate the junction temperature Tj of the electronic device D based on the heat flow (Id) due to the inspection power, the heat flow (Ic) in the holder temperature adjustment mechanism, the heat flow (Ip) in the detector temperature adjustment mechanism, the temperature (Tchuck) of the substrate holder, and the temperature (Tprob) of the detector. This allows for a reduction in packaging costs for the electronic device D compared to a configuration in which the electronic device is provided with an electrode unit E used only for detecting the junction temperature Tj. Also, the number of probes 12a provided on the probe card 12 can be reduced.

[0062] The heat flow (Id) due to the inspection power can be determined, for example, from the inspection power detected by the power detection unit 41. The heat flow (Ic) in the holding unit temperature adjustment mechanism can be determined, for example, from the input power of the power supply 25. The heat flow (Ip) in the detection unit temperature adjustment mechanism can be determined, for example, from the input power of the power supply 55.

[0063] The control unit 90 then controls the holding unit temperature adjustment mechanism and the detection unit temperature adjustment mechanism so that the junction temperature Tj becomes the inspection temperature. As a result, when inspecting the electronic device D, the junction temperature Tj of the electronic device D can be set to the inspection temperature, allowing the inspection to be performed preferably. In addition, a decrease in the yield of the electronic device D can be prevented.

[0064] Additionally, the control unit 90 controls the holder temperature adjustment mechanism and the detection unit temperature adjustment mechanism so that the temperature difference between the substrate W and the probe card 12 is within a predetermined threshold value. This suppresses the thermal expansion difference and prevents the probe 12 a from coming off the electrode portion E. It is also possible to suppress friction between the probe 12 a and the electrode portion E.

[0065] In addition, the analysis unit 93 of the control unit 90 calculates the holding unit target temperature and the detection unit target temperature based on the heat flow due to the inspection power (Id), the heat flow in the holding unit temperature adjustment mechanism (Ic), the heat flow in the detection unit temperature adjustment mechanism (Ip), the temperature of the substrate holding unit (Tchuck), and the temperature of the detection unit (Tprob).

[0066] The holding unit temperature control unit 91 controls the temperature of the substrate holding unit to the holding unit target temperature. In other words, the holding unit temperature control unit 91 controls the power supply 25 of the heater 20 and / or the chiller 26 so that the temperature Tchuck detected by the temperature detection unit 30 approaches the holding unit target temperature. The detection unit temperature control unit 92 also controls the temperature of the detection unit to the detection unit target temperature. In other words, the detection unit temperature control unit 92 controls the power supply 55 of the temperature adjustment mechanism 50 so that the temperature Tprob detected by the temperature detection unit 60 approaches the detection unit target temperature.

[0067] Here, the holding unit target temperature and the detection unit target temperature are set so that the estimated junction temperature Tj approaches the inspection temperature. As a result, when inspecting the electronic device D, the junction temperature Tj of the electronic device D can be set as the inspection temperature, allowing the inspection to be performed preferably. In addition, a decrease in the yield of the electronic device D can be prevented.

[0068] The holding unit target temperature and the detecting unit target temperature are set so that the difference between the estimated junction temperature Tj and the temperature Tprob of the probe card 12 is equal to or less than a threshold value. This suppresses the thermal expansion difference and prevents the probe 12a from coming off the electrode portion E. It is also possible to suppress friction between the probe 12a and the electrode portion E.

[0069] Next, a model of the temperature Tchuck of the stage 10 and the junction temperature Tj of the electronic device D will be described with reference to Fig. 8. Fig. 8 is a diagram showing a model of the temperature Tchuck of the stage 10 and the junction temperature Tj of the electronic device D. In Fig. 8, the inflow and outflow of heat are shown as the inflow and outflow of fluid.

[0070] The thermal tank 801 indicates the heat capacity of the stage 10. The liquid level in the thermal tank 801 corresponds to the temperature Tchuck. The thermal tank 802 indicates the heat capacity of the electronic device D. The liquid level in the thermal tank 802 corresponds to the junction temperature Tj. The heat flow path 803 connecting the thermal tanks 801 and 802 corresponds to the heat transfer between the stage 10 and the electronic device D. The narrowness of the flow path cross-sectional area of ​​the heat flow path 803 corresponds to the thermal resistance Rdc between the stage 10 and the electronic device D.

[0071] A heat inflow portion 804 to the thermal tank 801 corresponds to the amount of heat generated by the heater 20 (heating portion) that heats the stage 10. A heat inflow portion 805 to the thermal tank 802 corresponds to the amount of heat generated by the test power supplied to the electronic device D (test power detected by the power detection portion 41). A heat outflow portion 806 from the thermal tank 801 corresponds to the amount of heat dissipated from the stage 10 to the atmosphere. A heat outflow portion 807 from the thermal tank 801 corresponds to the amount of heat dissipated from the stage 10 to the chiller 26. Note that the heat outflow portion 807 is provided with a high-speed valve 808 that can be opened and closed at high speed between the thermal tank 801 and the chiller 809. The amount of heat dissipated from the stage 10 to the chiller 26 is controlled by controlling the high-speed valve 808.

[0072] Here, in order to evaluate the characteristics of the electronic devices D on the substrate W, the substrate W is vacuum-sucked onto the stage 10, and inspection power is supplied to the electronic devices D to inspect the electronic devices D. As the heat generation density of the electronic devices D increases, the thermal resistance (corresponding to the flow path cross-sectional area of ​​the heat flow path 803 shown in FIG. 8 ) between the electronic devices D and the stage 10 becomes non-negligible. Due to the thermal resistance between the electronic devices D and the stage 10, the temperature difference between the electronic devices D and the stage 10 during inspection can be several tens of degrees Celsius. In other words, the electronic devices D are inspected at a temperature higher than the inspection temperature, which may reduce the yield of the electronic devices D.

[0073] In response to this, inspection can be performed favorably by estimating the junction temperature Tj as shown in Figures 4 to 7. However, even in this case, when controlling the temperature Tchuck of the stage 10 so that the junction temperature Tj becomes a predetermined temperature, there is a risk that the junction temperature Tj will overshoot the predetermined temperature due to the thermal resistance between the electronic device D and the stage 10.

[0074] FIG. 9 is a flowchart illustrating an example of a method for controlling the junction temperature Tj of the electronic device D.

[0075] In step S101, a first transfer function of the rise in die temperature from die heat generation during testing is modeled and obtained. Here, the control unit 90 models and obtains the first transfer function, which is the relationship between heat generation (die heat generation) due to supplying testing power to the electronic device D (die) and the rise in junction temperature Tj (die temperature) of the electronic device D. The first transfer function is obtained based on data obtained by simulation, experiment, etc.

[0076] In step S102, the control unit 90 models and obtains a second transfer function of the chuck temperature when the set chuck temperature is changed. Here, when the set temperature of the stage 10 (set chuck temperature) is changed, the control unit 90 models and obtains a second transfer function of the temperature Tchuck (chuck temperature) of the stage 10 until it changes from the set temperature before the change to the set temperature after the change. The second transfer function is obtained based on data obtained by simulation, experiment, etc.

[0077] Here, the inspection temperature (junction temperature Tj) of the electronic device D during inspection is set to a first set temperature T1. The chuck set temperature before the start of inspection is set to the first set temperature T1. As a result, the temperature of the electronic device D placed on the stage 10 is also set to the first set temperature T1. Meanwhile, during inspection, the electronic device D generates heat when inspection power is supplied to it. For this reason, the chuck set temperature during inspection is set to a second set temperature T2 that is lower than the first set temperature T1, thereby bringing the inspection temperature (junction temperature Tj) of the electronic device D during inspection closer to the first set temperature T1.

[0078] In step S103, the control unit 90 calculates the chuck set temperature during inspection. Here, the control unit 90 determines the changed set temperature (the chuck set temperature during inspection, second set temperature T2: T2 = T1 - ΔT) by subtracting the increase (temperature difference ΔT) in the junction temperature Tj (die temperature) of the electronic device D when inspection power is supplied to the electronic device D (die) in step S101 from the set temperature before the change (first set temperature T1).

[0079] In step S104, the control unit 90 calculates a reference response waveform of the chuck temperature (a reference temperature change profile) for changing the temperature from the first set temperature T1 to the second set temperature T2 so that the junction temperature Tj of the electronic device D does not overshoot and / or undershoot.

[0080] In step S105, the reference value of the die power is acquired. Here, the control unit 90 acquires information such as the test power (die power) when testing the electronic device D from the tester 4. Note that, in testing the electronic device D, the amount of heat generated by each electronic device D differs depending on the characteristics of each electronic device D. For this reason, in step S105, the reference value of the test power (reference value of die power), which is an approximate test power of the electronic device D, is acquired.

[0081] In step S106, the control unit 90 generates a target trajectory for the chuck temperature based on the reference value of the inspection power (reference value of the die power) obtained in step S105, the first transfer function obtained in step S101, the second transfer function obtained in step S102, and the reference response waveform obtained in step S104.

[0082] In step S107, the control unit 90 controls the chuck temperature by changing the temperature Tchuck (chuck temperature) of the stage 10 from the first set temperature T1 to the second set temperature T2 based on the target trajectory of the chuck temperature created in step S106.

[0083] In step S108, the control unit 90 applies the die power to start the inspection and performs power following control. Here, the control unit 90 applies the inspection power (die power) to the electronic device D to start the inspection of the electronic device D, and also incorporates the inspection power (die power) into a control model to perform feedforward control (power following control) to control the temperature Tchuck (chuck temperature) of the stage 10 to the second set temperature T2.

[0084] In step S109, the control unit 90 controls the junction temperature Tj so that the junction temperature Tj becomes the first set temperature T1.

[0085] In the above description, after applying the inspection power to the electronic device D to be inspected, the temperature Tchuck (chuck temperature) of the stage 10 is controlled to the second set temperature T2 based on the inspection power in step S108, and then the junction temperature Tj of the stage 10 of the electronic device D is controlled to the first set temperature T1 based on the inspection power in step S109. However, this is not limited to this. Steps S108 and S109 may be combined into a single step, and after applying the inspection power to the electronic device D to be inspected, the junction temperature Tj of the stage 10 of the electronic device D may be controlled to the first set temperature T1 based on the inspection power. That is, the junction temperature Tj estimated from the control model, or the directly observed junction temperature Tj if directly observable, is controlled to the target temperature (first set temperature T1) of the electronic device D. In this case, the inspection power applied to the electronic device D may be controlled as a disturbance.

[0086] 10 is a graph showing an example of temperature control of the temperature Tchuck of the stage 10 and the junction temperature Tj of the electronic device D. Here, the horizontal axis represents time (sec) and the vertical axis represents temperature. The junction temperature Tj of the electronic device D is shown by a solid line, and the temperature Tchuck of the stage 10 is shown by a dashed line. The processing of steps S101 to S104 will be described assuming that it has been completed in advance.

[0087] In step S201, the control unit 90 controls the temperature so that the temperature Tchuck of the stage 10 becomes the first set temperature T1. Note that in step S201, no inspection power is applied to the electronic device D. As a result, the temperature Tchuck of the stage 10 and the junction temperature Tj of the electronic device D become the first set temperature T1.

[0088] At time ST0 in step S201, the control unit 90 acquires information on the inspection of the electronic device D from the tester 4 (see step S105). imp The information includes information on the time (from time ST0 when the inspection information is acquired to time ST2 when the inspection starts), and a reference value of the inspection power supplied to the electronic device D during the inspection.

[0089] Here, the control unit 90 generates a target trajectory for the temperature Tchuck (chuck temperature) of the stage 10 based on the information acquired from the tester 4 (see step S106). The control unit 90 calculates the temperature rise (temperature difference ΔT) based on the reference value of the test power supplied to the electronic device D during testing and the first transfer function model generated in step S101. The control unit 90 then subtracts the temperature rise (temperature difference ΔT) from the first set temperature T1 and sets the result as the second set temperature T2 (T2 = T1 - ΔT). The control unit 90 then generates a target trajectory for changing the temperature Tchuck (chuck temperature) of the stage 10 from the first set temperature T1 to the second set temperature T2 based on the second transfer function model generated in step S102 and the reference response waveform generated in step S104. Furthermore, the control unit 90 obtains, from the generated target trajectory, a response time t for changing the temperature Tchuck (chuck temperature) of the stage 10 from the first set temperature T1 to the second set temperature T2.

[0090] The control unit 90 also generates a target trajectory for changing the temperature Tchuck (chuck temperature) of the stage 10 from the second set temperature T2 to the first set temperature T1.

[0091] The time from ST0 when the test information was acquired from the tester 4 to the time (t imp At time ST1 after the response time t (-t) has elapsed, that is, at time ST1 before the response time t from time ST2 when the inspection starts, temperature control of the temperature Tchuck (chuck temperature) of the stage 10 using the target trajectory is started (see step S107).

[0092] In step S202 (step S107), the temperature Tchuck (chuck temperature) of the stage 10 is controlled using the target trajectory generated in step S106. Note that in step S202, no inspection power is applied to the electronic device D. As a result, the temperature Tchuck (chuck temperature) of the stage 10 decreases from the first set temperature T1 to the second set temperature T2. Furthermore, the junction temperature Tj of the electronic device D decreases from the first set temperature T1 to the second set temperature T2, following the temperature Tchuck of the stage 10.

[0093] At time ST2, testing of the electronic device D is started. That is, testing power is applied to the electronic device D (see step S108). This causes the junction temperature Tj of the electronic device D to rise.

[0094] In process S203 (step S108), the inspection power (die power) is incorporated into the control model, and the temperature Tchuck (chuck temperature) of the stage 10 is controlled (power following control) to become the second set temperature T2 by feedforward control.

[0095] After the transition period in which the junction temperature Tj fluctuates has passed, the process proceeds from step S203 to step S204 at time ST3. Here, the transition period may be determined to have passed after a predetermined time has passed since time ST2, when the inspection of the electronic device D began. Alternatively, the transition period may be determined to have passed when the amount of fluctuation in the junction temperature Tj falls within a predetermined range.

[0096] In process S204 (step S109), the control unit 90 controls the temperature so that the junction temperature Tj becomes the first set temperature T1.

[0097] At time ST4, the inspection of the electronic device D ends.

[0098] In step S205, the temperature Tchuck (chuck temperature) of the stage 10 is controlled on the target trajectory. Note that in step S205, no inspection power is applied to the electronic device D. As a result, the temperature Tchuck (chuck temperature) of the stage 10 rises from the second set temperature T2 to the first set temperature T1. As a result, the temperature Tchuck (chuck temperature) of the stage 10 and the junction temperature Tj of the electronic device D become the first set temperature T1.

[0099] 9 and 10 , it is possible to suppress overshoot and / or undershoot of the junction temperature Tj. That is, when the inspection power is applied to the electronic device D, it is possible to suppress fluctuations in the junction temperature Tj of the electronic device D within a predetermined range including the first set temperature T1 (for example, within ±3°C of the temperature T1 (within the range of T1-3°C to T1+3°C)). That is, it is possible to shorten the time from when the inspection power is applied to the electronic device D until the junction temperature Tj stabilizes and the inspection can be started. Furthermore, since it is possible to suppress overshoot of the junction temperature Tj of the electronic device D, it is possible to prevent the electronic device D from being thermally destroyed. Furthermore, it is possible to prevent a decrease in the yield of the electronic device D.

[0100] The above describes the inspection system 1, but the present disclosure is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the gist of the present disclosure described in the claims.

[0101] This application claims priority based on Japanese Patent Application No. 2024-044178, filed on March 19, 2024, the entire contents of which are incorporated herein by reference.

[0102] W: Substrate D: Electronic device E: Electrode section 1: Inspection system 2: Storage chamber 3: Loader 4: Tester 10: Stage 10a: Coolant flow path 12: Probe card 12a: Probe 13: Interface 14: Temperature control unit 20: Heater 25: Power supply 26: Chiller 30: Temperature detection section 41: Power detection section 50: Temperature adjustment mechanism 55: Power supply 90: Control section 91: Holding section temperature control section 92: Detection section temperature control section 93: Analysis section 60: Temperature detection section

Claims

1. A temperature control method for an inspection system comprising: a chuck for holding a substrate having an electronic device to be inspected; and a tester for inspecting the electronic device by applying inspection power to the electronic device, the method comprising: a step of modeling and determining a first transfer function of the temperature rise of the electronic device from heat generated by applying the inspection power to the electronic device; a step of modeling and determining a second transfer function of the temperature of the chuck when the set temperature of the chuck is changed; a step of obtaining the inspection timing of the electronic device from the tester; and a step of starting temperature control of the chuck based on the first transfer function and the second transfer function before inspection of the electronic device begins.

2. A temperature control method for an inspection system as described in claim 1, wherein the amount of temperature rise of the electronic device when the inspection power is applied to the electronic device is defined as a temperature rise amount ΔT, the set temperature of the electronic device when inspecting the electronic device is defined as a first set temperature T1, and the temperature obtained by subtracting the amount of temperature rise ΔT from the first set temperature T1 is defined as a second set temperature T2, and the step of starting temperature control of the chuck before inspection of the electronic device begins controls the temperature of the chuck from the first set temperature T1 to the second set temperature T2.

3. A temperature control method for an inspection system as described in claim 2, wherein the process of generating a target trajectory for controlling the temperature of the chuck from the first set temperature T1 to the second set temperature T2, calculating a response time of the target trajectory, and starting temperature control of the chuck before inspection of the electronic device begins controls the temperature of the chuck from the first set temperature T1 to the second set temperature T2 based on the target trajectory before the response time from the inspection timing.

4. The temperature control method for an inspection system according to claim 3, further comprising the step of controlling the temperature of the chuck to the second set temperature T2 based on the inspection power after applying the inspection power to the electronic device to be inspected.

5. The temperature control method for an inspection system according to claim 3, further comprising a step of controlling the temperature of the electronic device to the first set temperature T1 based on the inspection power after applying the inspection power to the electronic device to be inspected.

6. The temperature control method for an inspection system according to claim 4, further comprising a step of controlling the temperature of the electronic device to the first set temperature based on the inspection power after a transient period of temperature change of the electronic device has passed after applying the inspection power to the electronic device under inspection.

7. An inspection system comprising: a chuck for holding a substrate having an electronic device to be inspected; a tester for inspecting the electronic device by applying inspection power to the electronic device; and a control unit, wherein the control unit performs the steps of: modeling and determining a first transfer function of the temperature rise of the electronic device from heat generated by applying the inspection power to the electronic device; modeling and determining a second transfer function of the temperature of the chuck when the set temperature of the chuck is changed; obtaining the inspection timing of the electronic device from the tester; and starting temperature control of the chuck based on the first transfer function and the second transfer function before inspection of the electronic device begins.

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