Inspection system and inspection method

Abstract

Provided is an inspection system comprising: a first cooling unit for supplying a first heat medium controlled to a first temperature; a second cooling unit for supplying a second heat medium controlled to a second temperature lower than the first temperature; a mounting table provided with a flow path through which a heat medium having a desired mixing ratio of the first heat medium and the second heat medium is supplied; and a control unit, wherein the inspection system is configured to inspect a substrate mounted on the mounting table, the control unit controlling the following processes: a measuring process for measuring the temperature of the heat medium at an inlet of the flow path and the temperature of the heat medium at an outlet of the flow path; and a correction process for correcting the mixing ratio of the first heat medium to the second heat medium based on a difference between the temperatures of the heat medium at the inlet and the outlet and a flow rate of the heat medium.

Description

Technical Field

[0001] The present invention relates to an inspection system and an inspection method. Background Art

[0002] For example, Patent Document 1 discloses a temperature control method for a plasma etching device. In Patent Document 1, the heat load Q on the wafer during processing is calculated based on the high-frequency power applied to the lower electrode using a previously determined linear approximation for heat calculation. Next, based on the heat load, a target difference ΔT, the theoretical temperature difference between the inlet and outlet temperatures of the refrigerant circulation path, is calculated. Temperature control is then performed based on this target difference ΔT.

[0003] <Prior Art Literature>

[0004] <Patent Document>

[0005] Patent Document 1: Japanese Patent Application Publication No. 2001-044176 Summary of the Invention

[0006] <Problems to be Solved by the Invention>

[0007] The present invention provides an inspection system capable of adjusting the temperature of a substrate according to the thermal impedance between the substrate and a flow path.

[0008] <Methods used to solve the problem>

[0009] According to one embodiment of the present invention, an inspection system is provided, comprising: a first cooling unit for supplying a first heat medium controlled to a first temperature; a second cooling unit for supplying a second heat medium controlled to a second temperature lower than the first temperature; a mounting table provided with a flow path, the flow path being supplied with a heat medium that mixes the first heat medium and the second heat medium to a desired mixing ratio; and a control unit, the inspection system being used to inspect a substrate mounted on the mounting table, the control unit controlling the following processes: a measuring process for measuring the temperature of the heat medium at an inlet of the flow path and the temperature of the heat medium at an outlet of the flow path; and a correction process for correcting the mixing ratio of the first heat medium and the second heat medium based on a difference between the temperatures of the heat medium at the inlet and the outlet and a flow rate of the heat medium.

[0010] <Effects of the Invention>

[0011] According to the present invention, the temperature of the substrate can be adjusted based on the thermal impedance between the substrate and the flow path in the inspection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1It is a planar cross-sectional view showing a schematic configuration of the inspection system according to the present embodiment.

[0013] Figure 2 It is a front longitudinal sectional view showing a schematic configuration of the inspection system according to the present embodiment.

[0014] Figure 3 It is a front longitudinal sectional view showing the structure of the inspection area of the inspection system according to the present embodiment.

[0015] Figure 4 This is a partially enlarged view showing details of a tester of the inspection system according to this embodiment.

[0016] Figure 5 It is a cross-sectional view showing details of the chuck upper end member of the inspection system according to the present embodiment.

[0017] Figure 6 This is a diagram for explaining the thermal relationship of the chuck upper end member of the inspection system according to this embodiment.

[0018] Figure 7 It is a diagram for explaining the flow path of the heat medium in the inspection system according to the present embodiment.

[0019] Figure 8 This is a functional block diagram of the inspection system according to this embodiment.

[0020] Figure 9 This is a flowchart for explaining the processing of the inspection system according to this embodiment.

[0021] Figure 10 This is a diagram explaining the temperature when the inspection system according to this embodiment is operated.

[0022] Figure 11 This is a diagram explaining the temperature when the inspection system of the comparative example is operated.

[0023] Figure 12 It is a diagram for explaining a flow path of a heat medium in a modified example of the inspection system according to the present embodiment.

[0024] Figure 13 It is a diagram for explaining a flow path of a heat medium in a modified example of the inspection system according to the present embodiment. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiment of the present invention will be described with reference to the accompanying drawings. It should be noted that in this specification and the accompanying drawings, substantially the same components are given the same reference numerals and repeated descriptions are omitted.

[0026] <Overall configuration of the inspection system>

[0027] Figure 1 It is a planar transverse sectional view showing a schematic configuration of the inspection system 1 according to the present embodiment. Figure 2 It is a front longitudinal sectional view showing a schematic configuration of the inspection system 1 according to the present embodiment.

[0028] An inspection system 1 that inspects electrical characteristics based on a set temperature for each wafer W, as an example of a substrate, includes a housing 10 . The interior of the housing 10 is divided into a loading / unloading area 11 , a conveying area 12 , and an inspection area 13 .

[0029] The loading / unloading area 11 is used to load pre-inspected wafers W into the inspection system 1 and unload inspected wafers W from the inspection system 1. It is also used to load and unload probe cards 80, described later, into and out of the inspection system 1. The loading / unloading area 11 houses a mouth 20 for receiving a cassette C containing multiple wafers W and a loader 21 for accommodating the probe cards 80, described later. Furthermore, the loading / unloading area 11 houses a control unit 22 for controlling the various components of the inspection system 1.

[0030] The transport area 12 is used to transport wafers W and other components between the loading / unloading area 11 and the inspection area 13. A transport device 30 is located in the transport area 12, capable of freely moving while holding the wafers W and other components. The transport device 30 transports wafers W between a cassette C within the entrance 20 of the loading / unloading area 11 and an alignment unit 50, described later, in the inspection area 13. The transport device 30 also transports probe cards 80 requiring maintenance, which are secured to a spring frame 70, described later, within the inspection area 13, to the loader 21 in the loading / unloading area 11. Furthermore, the transport device 30 transports new or maintained probe cards 80 from the loader 21 to the spring frame 70 within the inspection area 13.

[0031] The inspection area 13 is an area for inspecting the electrical characteristics of electronic devices formed on the wafer W. In the inspection area 13, a plurality of testers 40 as inspection units are provided. Specifically, Figure 2 As shown, the inspection area 13 is divided into three areas in the vertical direction. In each divided area 13a, there is a Figure 2 The tester row consists of four testers 40 arranged horizontally. Each divided area 13a is equipped with an alignment unit 50 and a camera 60. It should be noted that the number and arrangement of the testers 40, alignment unit 50, and camera 60 can be arbitrarily selected. The testers 40 transmit and receive electrical signals for electrical characteristic inspection to and from the wafer W.

[0032] The alignment unit 50 includes a chuck upper end member 51 and an aligner 53. Details of the chuck upper end member 51 and the aligner 53 will be described later. The alignment unit 50 mounts a wafer W, serving as a substrate. Furthermore, the alignment unit 50 aligns the mounted wafer W with the probe card 80 positioned below the tester 40. The alignment unit 50 is movable within the area below the tester 40 for alignment.

[0033] The camera 60 captures the positional relationship between the probe card 80 disposed below the tester 40 and the wafer W placed on the alignment unit 50. The camera 60 moves horizontally and is positioned in front of each tester 40 within the divided area 13a where the camera 60 is disposed.

[0034] In the inspection system 1 of this embodiment, while the conveying device 30 conveys the wafer W to one of the multiple testers 40 in the divided area 13a, the other testers 40 in the divided area 13a can inspect the electrical characteristics of electronic devices formed on other wafers W.

[0035] Next, use Figure 3 as well as Figure 4 , the tester 40, the alignment unit 50 and the related structures are described in detail. Figure 3 It is a front longitudinal sectional view showing the configuration of the inspection area 13 of the inspection system 1 according to the present embodiment. Figure 4 It is a partially enlarged view showing details of the tester 40 of the inspection system 1 according to the present embodiment.

[0036] like Figure 3 as well as Figure 4 As shown, the tester 40 has a tester motherboard 41 horizontally arranged at the bottom of the tester 40. A plurality of inspection circuit boards (not shown) are mounted in a vertical position on the tester motherboard 41. In addition, a plurality of electrodes are provided on the bottom surface of the tester motherboard 41.

[0037] Furthermore, a spring frame 70 and a probe card 80 are provided below the tester 40 in order from the upper side.

[0038] Multiple support walls 10b extend vertically downward from the upper wall 10a of each partitioned area 13a around the tester 40. Spring frames 70 are attached to the lower portions of the opposing support walls 10b. Each tester 40 is supported by these opposing support walls 10b and the spring frames 70 interposed between them.

[0039] The spring frame 70 supports the probe card 80 and electrically connects the probe card 80 to the tester 40. The spring frame 70 is positioned between the tester 40 and the probe card 80. The spring frame 70 includes spring pins that electrically connect the tester 40 and the probe card 80. Specifically, the spring frame 70 includes a spring pin holder 72 for holding a plurality of spring pins, and a frame body 73 having mounting holes 73a formed therein for mounting the spring pins by inserting the spring pin holder 72. The frame body 73 is made of a material having high strength, high rigidity, and a low thermal expansion coefficient, such as a NiFe alloy. It should be noted that the use of a NiFe alloy allows the thermal conductivity of the frame body 73 to be set higher.

[0040] The probe card 80 is vacuum-adsorbed on the lower surface of the spring frame 70 while being aligned with a predetermined position.

[0041] Furthermore, a bellows 74 extending vertically downward is attached to the lower surface of the spring frame 70 so as to surround the mounting position of the probe card 80. This bellows 74 forms a sealed space encompassing the probe card 80 and the wafer W. Within this sealed space, the wafer W on the chuck upper end member 51 (described later) comes into contact with probes 82 of the probe card 80 (described later).

[0042] Furthermore, a vacuum mechanism (not shown) applies a vacuum suction force to the spring frame 70 and the probe card 80. This vacuum suction force causes the lower ends of the spring pins on the spring frame 70 to contact corresponding electrode pads on the upper surface of a card body 81 (described later) of the probe card 80. Furthermore, this vacuum suction force causes the upper ends of the spring pins on the spring frame 70 to contact corresponding electrodes on the lower surface of the tester motherboard 41.

[0043] The probe card 80 includes a circular card body 81, multiple electrode pads (not shown) located on the upper surface of the card body 81, and multiple needle-shaped terminals, or probes 82, extending downward from the lower surface of the card body 81. The multiple electrodes located on the upper surface of the card body 81 are electrically connected to corresponding probes 82. Furthermore, during inspection, the probes 82 contact the electrode pads and solder bumps of the electronic components formed on the wafer W. Therefore, during electrical characteristic inspection, electrical signals for inspection are transmitted and received between the tester motherboard 41 and the electronic components on the wafer W via the spring pins, the electrodes located on the upper surface of the card body 81, and the probes 82.

[0044] The alignment unit 50 includes a chuck upper end member 51 and an aligner 53. The chuck upper end member 51 is detachably mounted on the aligner 53. A wafer W is mounted on the chuck upper end member 51. The chuck upper end member 51 also attracts the mounted wafer W. A temperature adjustment mechanism 52 is provided in the chuck upper end member 51. This temperature adjustment mechanism 52 adjusts the temperature of the chuck upper end member 51 during electrical characteristics testing. Temperature adjustment by the temperature adjustment mechanism 52 allows the temperature of the wafer W mounted on the chuck upper end member 51 to be adjusted to, for example, -30°C to +130°C during electrical characteristics testing.

[0045] In addition, the aligner 53 supports the chuck upper end member 51 so that the chuck upper end member 51 is aligned with the chuck upper end member 51. Figure 3 as well as Figure 4 The up and down directions, the front and back directions of the paper, and the left and right directions.

[0046] The alignment unit 50 aligns the wafer W on the chuck upper member 51 with the probes 82 of the probe card 80, while the wafer W is in contact. After this alignment, a sealed space is formed encompassing the probe card 80 and the wafer W. This sealed space is then evacuated by a vacuum mechanism (not shown). At this point, the aligner 53 moves downward, separating the chuck upper member 51 from the aligner 53 and causing it to be attracted to the spring frame 70.

[0047] <Chuck upper part>

[0048] Next, the chuck upper end member 51 of the inspection system 1 according to this embodiment will be described. Figure 5 This is a cross-sectional view showing the details of the chuck upper end component 51 of the inspection system 1 of this embodiment. Figure 5 FIG. 1 is a diagram showing a state where a wafer W is placed on the chuck upper end member 51 .

[0049] The chuck upper end member 51 of the inspection system 1 of this embodiment includes a top plate 55 and a cooling jacket 56. It should be noted that the cooling jacket 56 of the chuck upper end member 51 of this embodiment is an example of the temperature adjustment mechanism 52.

[0050] The top plate 55 is a member on which the wafer W is placed. A mechanism for sucking the wafer W is provided in the top plate 55 .

[0051] The cooling jacket 56 is a component for adjusting the temperature of the wafer W. A heat medium flow path 58 is formed inside the cooling jacket 56, through which the heat medium HM circulates. The heat medium flow path 58 is formed, for example, in a spiral shape when viewed from above. It should be noted that the top view shape of the heat medium flow path 58 is not limited to a spiral shape, and can be, for example, a zigzag shape. The heat medium introduced into the heat medium flow path 58 is connected to the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL described later via the inlet and outlet pipes 58a provided on the outside of the cooling jacket 56. It should be noted that a heater can be provided separately as a component for adjusting the temperature. The heat medium HM is a medium used to adjust the temperature of the wafer W. The heat medium HM is, for example, water, a coolant, etc. The heat medium HM can be used to cool the wafer W or to heat the wafer W.

[0052] Here, the thermal relationship of the chuck upper end member 51 of the inspection system 1 according to this embodiment will be described. Figure 6 This diagram illustrates the thermal relationships within the chuck upper member 51 of the inspection system 1 according to this embodiment. A thermal impedance (hereinafter referred to as "thermal impedance R1") exists between the wafer W and the top plate 55. Therefore, for example, if the wafer W generates heat, the temperature of the wafer W deviates from the temperature of the top plate 55. Similarly, a thermal impedance (hereinafter referred to as "thermal impedance R2") exists between the top plate 55 and the cooling jacket 56. Furthermore, a thermal impedance (hereinafter referred to as "thermal impedance R3") exists between the cooling jacket 56 and the heat medium HM. Thus, thermal impedances R1, R2, and R3 exist between the components that make up the chuck upper member 51.

[0053] Since there are no heat sources in the top plate 55 and the cooling jacket 56, their temperatures change in accordance with the temperature of the heat medium HM. Therefore, by adjusting the temperature of the heat medium HM, the temperatures of the top plate 55 and the cooling jacket 56 can be maintained at the temperature of the heat medium HM. However, if heat is generated by the wafer W, a temperature difference (difference) occurs between the wafer W and the top plate 55 due to the thermal impedance R1 between the wafer W and the top plate 55. Therefore, even if the temperature of the heat medium HM is controlled, the temperature of the wafer W rises compared to the temperature of the heat medium HM. Even if the top plate 55 and the cooling jacket 56 are maintained at the set temperature, the temperature of the wafer W rises compared to the set temperature. In the inspection system 1 of this embodiment, the heat generation Qw of the wafer W is measured and correction is performed based on this heat generation Qw to eliminate the thermal impedance R1 between the wafer W and the top plate 55. Thus, the temperature of the wafer W is controlled so that it reaches the set temperature. It should be noted that the chuck upper end member 51 is an example of a mounting table.

[0054] <Temperature Control of Heating Medium>

[0055] Next, the temperature control of the heat medium HM will be described. Figure 7 1 is a diagram for explaining the flow path of the heat medium HM in the inspection system 1 of the present embodiment. In the following description, heat medium HM having different temperatures and flow paths is described with different reference numerals.

[0056] The inspection system 1 of the present embodiment includes a high-temperature cooling unit ChilH, a low-temperature cooling unit ChilL, three-way valves MV1 and MV2 , and control valves MV3 and MV4 .

[0057] The high-temperature cooling unit ChilH supplies a heat medium HM (heat medium HM1) at a temperature Tch. The low-temperature cooling unit ChilL supplies a heat medium HM (heat medium HM2) at a temperature Tcl, which is lower than Tch. It should be noted that the high-temperature cooling unit ChilH is an example of a first cooling unit that supplies a first heat medium controlled to a first temperature, and the low-temperature cooling unit ChilL is an example of a second cooling unit that supplies a second heat medium controlled to a second temperature lower than the first temperature. Heat medium HM1 is an example of a first heat medium, and heat medium HM2 is an example of a second heat medium. Furthermore, temperature Tch is an example of a first temperature, and temperature Tcl is an example of a second temperature.

[0058] Three-way valves MV1 and MV2 each distribute heat medium HM1 or HM2 flowing in from a single inlet into two flow paths for outflow. Each valve includes an electric or pneumatic driver. This driver changes the opening of the valves MV1 and MV2 in response to an external control signal. This change in opening distributes heat medium HM1 or HM2 flowing into the valves MV1 and MV2, allowing them to flow out through the two flow paths.

[0059] Control valves MV3 and MV4 are on-off valves that control the flow rate by adjusting their opening. They can be constructed, for example, from gate valves or ball valves. They include an electric or pneumatic actuator. This actuator changes the opening of the control valves MV3 and MV4 in response to an external control signal. This change in opening causes the heat medium HM31 or HM32 to flow out of each control valve MV3 and MV4 in an amount corresponding to the opening.

[0060] Furthermore, the inspection system 1 of the present embodiment includes temperature detectors 100 , 101 , and 102 , and pressure detectors 111 and 112 .

[0061] Temperature detectors 100, 101, and 102 are devices for detecting temperature, such as resistance temperature detectors, thermocouples, and thermistors. Temperature detector 100 is located on the top plate 55 of the chuck upper end member 51 and measures the temperature of the top plate 55. Temperature detector 101 is located in the flow path where the heat medium HM3 flows into the chuck upper end member 51 and measures the temperature (inlet temperature) of the heat medium HM3 flowing into the chuck upper end member 51. Temperature detector 102 is located in the flow path where the heat medium HM3 flows out of the chuck upper end member 51 and measures the temperature (outlet temperature) of the heat medium HM3 discharged from the chuck upper end member 51. It should be noted that since temperature detectors 101 and 102 measure the temperature difference between the heat medium HM3 flowing into and out of the chuck upper end member 51, they are preferably located near the chuck upper end member 51.

[0062] Pressure detectors 111 and 112 are devices used to detect pressure. Pressure detector 111 is located in the flow path where the heat medium HM3 flows into the chuck upper end member 51. It measures the pressure (inlet pressure) of the heat medium HM3 flowing into the chuck upper end member 51. Pressure detector 112 is located in the flow path where the heat medium HM3 flows out of the chuck upper end member 51. It measures the pressure (outlet pressure) of the heat medium HM3 discharged from the chuck upper end member 51. It should be noted that since pressure detectors 111 and 112 measure the pressure difference between the heat medium HM3 flowing into the chuck upper end member 51 and the heat medium HM3 flowing out, they are preferably located near the chuck upper end member 51.

[0063] The flow path of heat medium HM will be described. Heat medium HM1 at a temperature of Tch supplied from the high-temperature cooling unit ChilH flows into the three-way valve MV1. Based on a control signal, the three-way valve MV1 diverts a portion of the incoming heat medium HM1 (heat medium HM11) to the flow path to the cooling jacket 56, while the remaining heat medium HM12 is diverted to the flow path back to the high-temperature cooling unit ChilH. In this way, the three-way valve MV1 allows a portion of the incoming heat medium HM1 to flow through the flow path of the cooling jacket 56. Similarly, heat medium HM2 at a temperature of Tcl supplied from the low-temperature cooling unit ChilL flows into the three-way valve MV2. Based on a control signal, the three-way valve MV2 diverts a portion of the incoming heat medium HM2 (heat medium HM21) to the flow path to the cooling jacket 56, while the remaining heat medium HM22 is diverted to the flow path back to the low-temperature cooling unit ChilL. In this way, the three-way valve MV2 allows a portion of the incoming heat medium HM2 to flow through the flow path of the cooling jacket 56. The heat media HM11 and HM21 that flow to the cooling jacket 56, which are diverted by the three-way valves MV1 and MV2, merge and mix along the way. The resulting mixture of the diverted heat media HM11 and HM21 is referred to as heat medium HM3. The temperature T1 of heat medium HM3 is determined by the respective temperatures and flow rates of heat medium HM11 supplied from the high-temperature cooling unit ChilH via the three-way valve MV1 and heat medium HM21 supplied from the low-temperature cooling unit ChilL via the three-way valve MV2. Temperature T1 is measured by the temperature detector 101. Furthermore, the pressure P1 of heat medium HM3 is measured by the pressure detector 111.

[0064] In this way, to dynamically change the temperature T1 of heat medium HM3, two systems of heat medium HM are mixed: high-temperature heat medium HM11 (heat medium HM1) and low-temperature heat medium HM21 (heat medium HM2). By mixing the two systems of heat medium HM in this way, the temperature of heat medium HM3 can be rapidly changed while being stabilized at a predetermined temperature.

[0065] Heat medium HM3, a mixture of heat medium HM11 and heat medium HM21, passes through cooling jacket 56. Heat medium HM3 passing through cooling jacket 56 regulates the temperature of wafer W via top plate 55. The temperature T2 and pressure P2 of heat medium HM3 exiting cooling jacket 56 are measured by temperature detector 102 and pressure detector 112, respectively. Heat medium HM3 exiting cooling jacket 56 then flows into control valves MV3 and MV4. Control valve MV3 directs heat medium HM31 at the same flow rate as heat medium HM11 exiting cooling jacket 56 from three-way valve MV1 to the flow path that returns to high-temperature cooling unit ChilH. Heat medium HM31 exiting control valve MV3 mixes with heat medium HM12 returning to high-temperature cooling unit ChilH from three-way valve MV1 (heat medium HM1R), and then returns to high-temperature cooling unit ChilH. Control valve MV4 allows heat medium HM32 to flow out of the cooling jacket 56 at the same flow rate as heat medium HM21 flowing out of the three-way valve MV2 into the flow path returning to the low-temperature cooling unit Chil-L. Heat medium HM32 flowing out of control valve MV4 mixes with heat medium HM22 returning to the low-temperature cooling unit Chil-L from the three-way valve MV2 (heat medium HM2R), and then returns to the low-temperature cooling unit Chil-L.

[0066] Note that heat medium HM3 is an example of a mixture of the first heat medium and the second heat medium at a desired mixing ratio. Furthermore, three-way valve MV1 (first three-way valve) and three-way valve MV2 (second three-way valve) are examples of valves at the outlet of the first cooling unit and the outlet of the second cooling unit.

[0067] <Control Unit>

[0068] Next, the control unit 22 for performing temperature control will be described. Figure 8 This is a functional block diagram of a portion related to temperature control of the inspection system 1 according to this embodiment.

[0069] The control unit 22 includes an overall control unit 201, a calculation unit 202, a valve control unit 203, and a data acquisition unit 204. The control unit 22 includes a storage device that stores programs in a readable manner, a CPU (Central Processing Unit) for executing the programs, etc. The control unit 22 operates as a computer.

[0070] The overall control unit 201 controls the entire control unit 22 .

[0071] The calculation unit 202 uses the data acquired by the data acquisition unit 204 to perform calculations for calculating the temperature difference, flow rate, calorific value, correction amount, mixing ratio, valve opening, etc. described later.

[0072] The valve control unit 203 controls the opening degree of each valve by sending control signals to the three-way valves MV1 and MV2 and the control valves MV3 and MV4, thereby controlling the amount of heat medium HM flowing out of each valve.

[0073] The data acquisition unit 204 acquires temperature and pressure data from the temperature detectors 100 , 101 , and 102 and the pressure detectors 111 and 112 , respectively.

[0074] <Wafer Temperature Control Method>

[0075] Next, the processing of the inspection system 1 according to this embodiment will be described. Figure 9 This is a flowchart for explaining the processing of the inspection system 1 of this embodiment. The inspection system 1 performs processing based on the following steps (sequence). It should be noted that in the inspection system 1 of this embodiment, while Figure 9 While processing, electrical tests on wafer W are performed.

[0076] (Step S10) When the operation of the inspection system 1 starts (for example, the inspection process starts), the control unit 22 performs an initialization process for initializing the inspection system 1. In the initialization process, for example, each functional unit of the control unit 22 is initialized.

[0077] (Step S20) The data acquisition unit 204 acquires temperature T1 from the temperature detector 101. Furthermore, the data acquisition unit 204 acquires temperature T2 from the temperature detector 102. Based on Equation 1, the calculation unit 202 calculates the temperature difference ΔT from the difference between temperature T1 and temperature T2 acquired by the data acquisition unit 204. It should be noted that temperature Ta is the difference between temperature T1 and temperature T2 when the wafer W is not heated. This temperature Ta is caused by a temperature rise due to heat generation from the resistance of the piping between the temperature detectors 101 and 102, for example.

[0078] (Mathematical formula 1)

[0079] ΔT=T2-T1-Ta

[0080] (Step S30) The data acquisition unit 204 acquires pressure P1 from the pressure detector 111. Furthermore, the data acquisition unit 204 acquires pressure P2 from the pressure detector 112. Based on Equation 2, the calculation unit 202 calculates the pressure difference ΔP between the pressures P1 and P2 acquired by the data acquisition unit 204. Using the calculated pressure difference ΔP, the flow rate Q of the heat medium HM (heat medium HM3) flowing through the cooling jacket 56 is calculated based on Equation 3. Note that K1 is a constant determined by, for example, the structure of the cooling jacket 56.

[0081] (Mathematical formula 2)

[0082] ΔP=P1-P2

[0083] (Mathematical formula 3)

[0084] Q=K1×ΔP

[0085] It should be noted that, in the inspection system 1 of this embodiment, the flow rate Q of the heat medium HM (heat medium HM3) is determined based on the pressure difference ΔP. However, this flow rate Q can be determined using other means. For example, a flow meter such as an electromagnetic flowmeter, a vane flowmeter, a Coriolis flowmeter, or an ultrasonic flowmeter can be used. Furthermore, a throttling device or the like can be provided in the heat medium flow path to measure the flow rate based on the pressure difference.

[0086] (Step S40) The calculation unit 202 estimates the heat generation Qw of the wafer W based on the obtained temperature difference ΔT and the flow rate Q according to Equation 4. Note that K2 is a constant determined by the thermal impedance R1 and the like.

[0087] (Mathematical formula 4)

[0088] Qw=K2×ΔT×Q

[0089] (Step S50 ) The calculation unit 202 obtains the correction value Tcor for controlling the temperature of the wafer W based on the obtained heat generation value Qw of the wafer W according to Equation 5. Note that K3 is a constant determined based on the thermal impedance R1 and the like.

[0090] (Mathematical formula 5)

[0091] Tcor=K3×Qw

[0092] As described above, when wafer W generates heat, due to the thermal impedance R1 between wafer W and top plate 55, even if the temperature of top plate 55 is set to the target temperature Tw of wafer W, the temperature of wafer W will deviate from the target temperature Tw. Therefore, in the inspection system 1 of this embodiment, control is performed to cause the temperature of top plate 55 to deviate from the target temperature Tw of wafer W by the correction value Tcor. That is, when controlling the temperature of wafer W to reach the target temperature Tw, the temperature of top plate 55 is set to the target temperature Ttp as shown in Equation 6. When the temperature of top plate 55 is set to the target temperature Ttp, the temperature of heat medium HM3 supplied to chuck upper end member 51 (cooling jacket 56) is set to the target temperature Ttp.

[0093] (Mathematical formula 6)

[0094] Ttp=Tw-Tcor

[0095] It should be noted that the target temperature Ttp can be changed based on the heat generation Qw of the wafer W. For example, when the heat generation Qw is low (when the heat generation Qw is less than a set threshold (below the threshold)), the target temperature Tw of the wafer W can be set. In this case, when the heat generation Qw is high (when the heat generation Qw is greater than the set threshold (above the threshold)), correction is performed using the correction value Tcor.

[0096] (Step S60) The calculation unit 202 calculates the mixing ratio Chm between the heat medium HM1 (temperature Tch) supplied by the high-temperature cooling unit ChilH and the heat medium HM2 (temperature Tcl) supplied by the low-temperature cooling unit ChilL. The calculation unit 202 calculates the mixing ratio Chm based on Equation 7 so that the heat medium HM3 obtained by mixing the heat medium HM1 and the heat medium HM2 reaches the target temperature Ttp. In the inspection system 1 of this embodiment, the mixing ratio is calculated as the ratio of the flow rates of the heat medium HM1 and the heat medium HM3. The flow rate of the heat medium HM (temperature Tch) supplied by the high-temperature cooling unit ChilH is set as flow rate Qh, and the flow rate of the heat medium HM (temperature Tcl) supplied by the low-temperature cooling unit ChilL is set as flow rate Ql.

[0097] (Mathematical formula 7)

[0098] Chm=Qh / (Ql+Qh)=(Ttp-Tcl) / (Tch-Tcl)

[0099] In this manner, the heating value Qw of the wafer W is calculated based on the difference between the temperatures T1 and T2 and the flow rate Q. Furthermore, the mixing ratio Chm is calculated based on the target temperature Ttp corrected using the correction value Tcor based on the heating value Qw of the wafer W. By calculating in this manner, the mixing ratio Chm can be corrected based on the difference between the temperatures T1 and T2 and the flow rate Q.

[0100] It should be noted that, in this embodiment, although the heating value Qw of the wafer W is calculated, the mixing ratio Chm can be corrected based on the difference between the temperatures T1 and T2 and the flow rate Q. For example, a chart that can directly correct the mixing ratio Chm based on the difference between the temperatures T1 and T2 and the flow rate Q can be prepared in advance, and the mixing ratio Chm can be calculated using this chart.

[0101] As described above, the control unit 22 controls the process of measuring temperature T1 and temperature T2 in step S20. Furthermore, the control unit 22 controls the process of measuring pressure P1 and pressure P2 in step S30. Furthermore, the control unit 22 controls the process of correcting the mixture ratio Chm in steps S20, S30, S40, S50, and S60.

[0102] (Step S70) The calculation unit 202 calculates the valve openings of the three-way valves MV1 and MV2 so as to achieve the calculated mixture ratio Chm. The valve control unit 203 then uses the calculated valve openings to control the openings of the three-way valves MV1 and MV2. Furthermore, the valve control unit 203 controls the openings of the control valves MV3 and MV4 accordingly.

[0103] (Step S80) The control unit 22 determines whether to terminate the process. If the process is terminated (Step S80: YES), the process proceeds to Step S90. If the process is not terminated (Step S80: NO), the process returns to Step S20 and repeats the process from Step S20.

[0104] (Step S90 ) A process for terminating the inspection system 1 is performed.

[0105] <Check system operation>

[0106] The operation of the inspection system 1 according to this embodiment will be described. Figure 10 It is a diagram for explaining the temperature when the inspection system 1 of this embodiment is operated. Figure 11 It is a diagram for explaining the temperature when the inspection system of the comparative example is operated. Figure 10 、 Figure 11 The case where the target temperature of the wafer W is set to 85° C. is shown. Figure 10 、 Figure 11 The horizontal axis represents the heat generation Qw of the wafer W, and the vertical axis represents the respective temperatures of the top plate 55, the wafer W, and the heat medium HM3.

[0107] In the inspection system 1 of this embodiment, as Figure 10 As shown, the target temperature Ttp (top plate set temperature) for adjusting the temperature of the top plate 55 is corrected according to the heating value Qw of the inspection target wafer W. Specifically, the larger the heating value Qw of the wafer W, the lower the top plate set temperature is set. Figure 10 The heat medium temperature represents the outlet temperature of heat medium HM3 (temperature T2). When wafer W is not generating heat, the heat medium temperature is 90°C. That is, Ta in equation 1 is 5°C. The top plate set temperature decreases as the heat generation Qw of wafer W increases. Consequently, the heat medium temperature decreases as the heat generation Qw increases. Consequently, the temperature of wafer W remains constant regardless of changes in the heat generation Qw of wafer W.

[0108] On the other hand, in the inspection system of the comparative example, Figure 11 As shown, regardless of the heat generation Qw at the wafer W, the target temperature Ttp (top plate set temperature) for adjusting the temperature of the top plate 55 is set constant. Therefore, the temperature of the heat medium is constant. Figure 11 The heat medium temperature represents the outlet temperature of heat medium HM3 (temperature T2). However, due to the heat generated by wafer W, Qw, a temperature difference occurs between top plate 55 and wafer W, causing the temperature of wafer W to rise. This heat generation causes the temperature of wafer W to rise above the set top plate temperature, making it impossible to control the target temperature of wafer W.

[0109] It should be noted that the temperature detector 101 is an example of a sensor for measuring the temperature of the heat medium at the inlet of the flow path. The temperature detector 102 is an example of a sensor for measuring the temperature of the heat medium at the outlet of the flow path. Furthermore, the pressure detector 111 is an example of a sensor for measuring the pressure of the heat medium at the inlet of the flow path. The pressure detector 112 is an example of a sensor for measuring the pressure of the heat medium at the outlet of the flow path.

[0110] <Function and Effect>

[0111] The inspection system 1 of this embodiment corrects the target temperature used to adjust the temperature of the top plate 55 based on the heat generated by the wafer W (substrate). Therefore, regardless of the heat generated by the wafer W (substrate), inspection can be performed based on the set temperature set for each substrate. This allows substrate temperature adjustment based on the thermal impedance between the substrate and the flow path.

[0112] Furthermore, the temperature of the cooling jacket 56 is adjusted by supplying a constant-temperature heat medium from the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL and mixing these heat media. This mixing of heat media allows the temperature of the heat medium HM to be dynamically changed. Furthermore, mixing heat media allows for rapid temperature changes. Rapid temperature changes can shorten inspection time.

[0113] Furthermore, by calculating the heating value Qw of the wafer W using the measurement results of temperature sensors and pressure sensors in the flow path of the heat medium HM, correction can be performed even without directly measuring the temperature of the wafer W. For example, to detect the temperature of the wafer W under inspection, it is necessary to obtain information from the tester 40. In this case, processing must be performed by the tester 40. In the inspection system 1 of this embodiment, since it is not necessary to obtain information from the tester 40, processing can be performed without relying on the tester 40.

[0114] It should be noted that while three-way valves MV1 and MV2 are used in this embodiment, they can also be configured as on-off valves, similar to control valves MV3 and MV4. In this case, a flow path from the three-way valves MV1 and MV2 to the downstream confluence point of the control valves MV3 and MV4 is unnecessary, simplifying the piping.

[0115] <Variation 1>

[0116] An example in which the flow path of the inspection system 1 according to the present embodiment is modified will be described. Figure 12 It is a diagram for explaining a flow path of a heat medium in Modification 1 of the inspection system according to the present embodiment.

[0117] The flow path of heat medium HM in Modification 1 will be described. Heat medium HM1 at temperature Tch, supplied from the high-temperature cooling unit ChilH, flows into heat exchanger HEX1. Similarly, heat medium HM2 at temperature Tcl, supplied from the low-temperature cooling unit ChilL, flows into heat exchanger HEX1. The flow rates of heat medium HM1 and heat medium HM2 are controlled by control valves MV5 and MV6, respectively. Heat exchange occurs in heat exchanger HEX1 between heat medium HM1 and heat medium HM2. As a result, the temperature of heat medium HM1 flowing out of heat exchanger HEX1 is lower than when it flows into heat exchanger HEX1. Furthermore, the temperature of heat medium HM1 flowing out of heat exchanger HEX1 can be controlled by adjusting the flow rates of heat medium HM1 and heat medium HM2, respectively.

[0118] When wafer W generates heat as described above, due to the thermal impedance R1 between wafer W and top plate 55, even if the temperature of top plate 55 is set to the target temperature Tw of wafer W, the temperature of wafer W will deviate from the target temperature Tw. Therefore, in the inspection system 1 of this embodiment, control is performed to cause the temperature of top plate 55 to deviate from the target temperature Tw of wafer W by a correction value Tcor. Specifically, when controlling the temperature of wafer W to achieve the target temperature Tw, the temperature of top plate 55 is set to the target temperature Ttp as shown in the above equation 6. When the temperature of top plate 55 is set to the target temperature Ttp, the temperature of heat medium HM3 supplied to chuck upper end member 51 (cooling jacket 56) is set to the target temperature Ttp. In this manner, control unit 22 controls the process for correcting the target temperature.

[0119] By using the flow path of the heat medium HM according to Modification 1, the temperature of the wafer W can be adjusted without mixing the heat media HM1 and HM2 supplied from the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL, respectively. Thus, for example, different heat media can be used as the heat media for the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL.

[0120] <Variation 2>

[0121] An example in which the flow path of the inspection system 1 according to the present embodiment is modified is shown. Figure 13 It is a diagram for explaining a flow path of a heat medium in a second modification of the inspection system according to the present embodiment.

[0122] The flow path of heat medium HM in Modification 2 will be described. Heat medium HM1 at temperature Tch supplied from high-temperature cooling unit ChilH is separated into heat medium HM11 and heat medium HM12. Heat medium HM11 flows into heat exchanger HEX2. Heat medium HM12 flows into three-way valve MV7. Similarly, heat medium HM2 at temperature Tcl supplied from low-temperature cooling unit ChilL is separated into heat medium HM21 and heat medium HM22. Heat medium HM21 flows into heat exchanger HEX2. Heat medium HM22 flows into three-way valve MV8. The flow rates of heat medium HM11 and heat medium HM21 are controlled by controlling the openings of three-way valves MV7 and MV8. Heat exchange occurs between heat medium HM11 and heat medium HM21 in heat exchanger HEX2. As a result, the temperature of heat medium HM11 flowing out of heat exchanger HEX2 is lower than when it flows into heat exchanger HEX2. Furthermore, the temperature of heat medium HM1 flowing out of heat exchanger HEX2 can be controlled by adjusting the flow rates of heat medium HM11 and heat medium HM21. Target temperature correction is the same as in Modification 1.

[0123] By using the heat medium HM flow path of Modification 2, the flow rates of heat medium HM1 and HM2 supplied from the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL, respectively, can be set to be substantially constant. This further stabilizes the temperatures of the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL.

[0124] It should be noted that in Modification 2, while three-way valves MV7 and MV8 are respectively installed in the heat medium return flow paths of the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL, their respective locations are not limited to these flow paths. For example, three-way valves MV7 and MV8 can be respectively installed in the heat medium supply flow paths of the high-temperature cooling unit ChilH and the low-temperature cooling unit ChilL, that is, in the flow paths that flow into the heat exchanger HEX2.

[0125] The inspection system and inspection method disclosed herein are intended in all respects to be illustrative and non-restrictive. The above-described embodiments may be modified and improved in various ways without departing from the scope of the appended claims and their spirit. The various embodiments described above may be modified and combined within the scope of non-inconsistency.

[0126] This application claims priority from basic patent application No. 2019-169728 filed in the Japan Patent Office on September 18, 2019, and the entire contents are incorporated herein by reference.

[0127] Description of Reference Numerals

[0128] 1. Check the system

[0129] 10 Housing

[0130] 22 Control Unit

[0131] 52 Temperature adjustment mechanism

[0132] 55 Top Plate

[0133] 56 Cooling Jacket

[0134] 58 Heat medium flow path

[0135] 60 cameras

[0136] 100 Temperature Detector

[0137] 101 Temperature Detector

[0138] 102 Temperature Detector

[0139] 111 Pressure Detector

[0140] 112 Pressure Detector

[0141] 202 Operation Unit

[0142] ChilH High temperature cooling unit

[0143] ChilL Low temperature cooling unit

[0144] MV1 three-way valve

[0145] MV2 three-way valve

[0146] MV3 control valve

[0147] MV4 control valve

Claims

1. An inspection system having: a first cooling unit for supplying a first heat medium controlled to a first temperature; a second cooling unit for supplying a second heat medium controlled to a second temperature lower than the first temperature; a mounting table provided with a flow path to which a mixed heat medium obtained by mixing the first heat medium and the second heat medium at a desired mixing ratio is supplied; and Control Department, The inspection system is used to inspect the substrate placed on the above-mentioned mounting table. The control unit controls the following processes: a measuring step of measuring the temperature of the mixed heat medium at the inlet of the flow path and the temperature of the mixed heat medium at the outlet of the flow path; a calculation step of calculating the calorific value of the substrate based on a difference in temperature between the mixed heat medium at an inlet of the flow path and an outlet of the flow path and a flow rate of the mixed heat medium flowing through the flow path; and a correction step of correcting the mixing ratio of the first heat medium and the second heat medium based on the calorific value to adjust the temperature of the substrate; The control unit controls the process of measuring the pressure of the mixed heat medium at the inlet of the flow path and the pressure of the mixed heat medium at the outlet of the flow path. The control unit obtains the flow rate of the mixed heat medium based on a difference in pressure between the mixed heat medium at an inlet of the flow path and at an outlet of the flow path.

2. The inspection system according to claim 1, wherein: The control unit controls the opening degree of the valve at the outlet of the first cooling unit and the opening degree of the valve at the outlet of the second cooling unit so as to achieve the corrected mixing ratio.

3. The inspection system according to claim 1 or 2, wherein: The valve at the outlet of the first cooling unit is a first three-way valve, which allows the first heat medium to flow in and allows a portion of the first heat medium to flow in the flow path. The valve at the outlet of the second cooling unit is a second three-way valve, which allows the second heat medium to flow in and allows a portion of the inflowing second heat medium to flow through the flow path.

4. An inspection system having: a first cooling unit for supplying a first heat medium controlled to a first temperature; a second cooling unit for supplying a second heat medium controlled to a second temperature lower than the first temperature; a mounting table provided with a flow path to which the first heat medium, which has been heat-exchanged and lowered to a desired target temperature by heat exchange between the first heat medium and the second heat medium, is supplied; and Control Department, The inspection system is used to inspect the substrate placed on the above-mentioned mounting table. The control unit controls the following processes: a measuring step of measuring a temperature of the first heat medium after heat exchange at an inlet of the flow path and a temperature of the first heat medium after heat exchange at an outlet of the flow path; a calculation step of calculating the heat generated by the substrate based on a difference in temperature between the first heat medium at an inlet of the flow path and an outlet of the flow path after heat exchange and a flow rate of the first heat medium after heat exchange flowing through the flow path; and a calibration step of calibrating the target temperature based on the calorific value to adjust the temperature of the substrate; The control unit controls the process of measuring the pressure of the first heat medium after the heat exchange at the inlet of the flow path and the pressure of the first heat medium after the heat exchange at the outlet of the flow path. The control unit obtains the flow rate of the first heat medium after the heat exchange based on a difference in pressure between the first heat medium after the heat exchange at an inlet of the flow path and an outlet of the flow path.

5. An inspection method for inspecting a substrate placed on a mounting table in an inspection system, the inspection system comprising: a first cooling unit for supplying a first heat medium controlled to a first temperature; a second cooling unit for supplying a second heat medium controlled to a second temperature lower than the first temperature; and The mounting table is provided with a flow path to which a mixed heat medium obtained by mixing the first heat medium and the second heat medium at a desired mixing ratio is supplied. The inspection method performs the following steps: a measuring step of measuring the temperature of the mixed heat medium at the inlet of the flow path and the temperature of the mixed heat medium at the outlet of the flow path; a calculation step of calculating the calorific value of the substrate based on a difference in temperature between the mixed heat medium at an inlet of the flow path and an outlet of the flow path and a flow rate of the mixed heat medium flowing through the flow path; and a correction step of correcting the mixing ratio of the first heat medium and the second heat medium based on the calorific value to adjust the temperature of the substrate; The process of measuring the pressure of the mixed heat medium at the inlet of the flow path and the pressure of the mixed heat medium at the outlet of the flow path is controlled. The flow rate of the mixed heat medium is obtained based on the difference between the pressure of the mixed heat medium at the inlet of the flow path and the pressure at the outlet of the flow path.

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