JP7304722B2 - Temperature control device, temperature control method, and inspection device - Google Patents

Description

The present disclosure relates to temperature control devices, temperature control methods, and inspection devices.

2. Description of the Related Art In a semiconductor manufacturing process, a large number of electronic devices having predetermined circuit patterns are formed on a semiconductor wafer (hereinafter simply referred to as wafer). The formed electronic devices are inspected for electrical characteristics and the like, and sorted into non-defective products and defective products. The inspection of electronic devices is performed using an inspection apparatus, for example, in a state of a wafer before each electronic device is divided.

An electronic device inspection apparatus includes a probe card having a large number of pin-shaped probes, a mounting table on which a wafer is mounted, and a tester (see Patent Document 1). This inspection equipment contacts each probe of the probe card to the electrode pads and solder bumps provided corresponding to the electrodes of the electronic device, and transmits the signal from the electronic device to the tester to inspect the electrical characteristics of the electronic device. do. In addition, when inspecting the electrical characteristics of an electronic device, the inspection apparatus of Patent Document 1 controls the temperature of the mounting table by means of coolant channels and heaters in the mounting table in order to reproduce the mounting environment of the electronic device. It has a temperature control device.

Further, Patent Document 2 describes that wafer temperature control is performed by sliding mode control using cooling water and a thermoelectric conversion module.

JP-A-10-135315 Japanese Patent Application Laid-Open No. 2002-318602

The present disclosure provides a temperature control device, a temperature control method, and an inspection device that can control the temperature of a temperature-controlled object with good controllability even when a disturbance occurs.

A temperature control device according to an aspect of the present disclosure is a temperature control device that performs temperature control of a temperature control target, comprising: a heating mechanism having a heating source that heats the temperature control target; a cooling mechanism having a cooling source for cooling; and a temperature controller for controlling the heating source and the cooling source. a sliding mode controller whose manipulated variable is the power applied to the cooling source; a cooling mode controller whose manipulated variable is the power applied to the cooling source; Depending on the value of , the output of the sliding mode controller is directly output to the heating source as the first manipulated variable, or the output of the cooling mode controller is used as the second manipulated variable without using the output of the sliding mode controller. a switching controller for determining whether to output to the cooling source as a quantity, wherein the switching controller switches to the sliding mode controller when the nonlinear term is in a region on one side of a switching hyperplane in sliding mode control. and switches to use the output of the cooling mode controller if it is in the region on the other side of the switching hyperplane.

A temperature control device according to another aspect of the present disclosure is a temperature control device that performs temperature control of a temperature control target, comprising: a heating mechanism having a heating source that heats the temperature control target; and a temperature controller for controlling the heating source and the cooling source, wherein the temperature controller controls the temperature measurement value of the temperature controlled object, and the heating a sliding mode controller whose manipulated variable is the power applied to the cooling source; a cooling mode controller whose manipulated variable is the power applied to the cooling source; Depending on the value of the term, the output of the sliding mode controller is directly output to the heating source as the first manipulated variable, or the sum of the output of the sliding mode controller and the output of the cooling mode controller is output to the second and a switching controller that determines whether to use as the manipulated variable of the .

According to the present disclosure, there are provided a temperature control device, temperature control method, and inspection device that can control the temperature of a temperature-controlled object with good controllability even when a disturbance occurs.

It is a perspective view showing a schematic structure of an inspection device concerning a 1st embodiment. It is a front view which shows a part of inspection apparatus of FIG. 1 in a cross section. 1 is a plan view schematically showing the configuration of a wafer as a substrate that is an object to be inspected; FIG. FIG. 4 is a cross-sectional view schematically showing the upper structure of the stage and the temperature control device; It is a top view which shows the structure of a heating mechanism roughly. FIG. 4 is a diagram schematically showing the configuration of a temperature measurement circuit of an electronic device; FIG. 4 is a diagram for explaining sliding mode control; 4 is a block diagram showing control blocks of a temperature controller in the inspection apparatus according to the first embodiment; FIG. 9 is a block diagram showing the inside of a sliding mode controller in the temperature controller of FIG. 8; FIG. FIG. 10 is a block diagram showing the non-linear input section of the sliding mode controller of FIG. 9; FIG. 9 is a block diagram showing the configuration of a cooling mode controller and a switching controller in the temperature controller of FIG. 8 and transmission and reception of these signals; It is a block diagram showing the inside of a plant model. FIG. 9 is a block diagram showing control blocks of a temperature controller in the inspection apparatus according to the second embodiment; FIG. 14 is a block diagram showing the inside of a cooling mode controller and a switching controller in the temperature controller of FIG. 13 and transmission and reception of these signals; FIG. 10 is a diagram showing a simulation result when the temperature of the chip is controlled by sliding mode control and the heat generation disturbance is 150 W; FIG. 10 is a diagram showing a simulation result when the temperature of the chip is controlled by sliding mode control and the heat generation disturbance is 300 W; FIG. 10 is a diagram showing a simulation result when the temperature of the chip is controlled by sliding mode control and the heat disturbance is 450 W; FIG. 10 is a diagram showing a simulation result when the heat disturbance is 150 W when the temperature of the chip is controlled by the control of the first embodiment; FIG. 10 is a diagram showing a simulation result when the heat disturbance is 300 W when the temperature of the chip is controlled by the control of the first embodiment; FIG. 10 is a diagram showing a simulation result when the heat disturbance is 450 W when the temperature of the chip is controlled by the control of the first embodiment; FIG. 10 is a diagram showing a simulation result when heat generation disturbance is 150 W when chip temperature control is performed by the control of the second embodiment; FIG. 10 is a diagram showing a simulation result when the temperature of the chip is controlled by the control of the second embodiment and the heat generation disturbance is 300 W; FIG. 10 is a diagram showing a simulation result when the temperature of the chip is controlled by the control of the second embodiment and the heat disturbance is 450 W; FIG. 11 is an enlarged diagram showing simulation results of the first embodiment when heat generation disturbance is 150 W; FIG. 11 is an enlarged view showing simulation results of the second embodiment when heat generation disturbance is 150 W; FIG. 10 is an enlarged diagram showing simulation results of the first embodiment when heat generation disturbance is 300 W; FIG. 11 is an enlarged view showing simulation results of the second embodiment when heat generation disturbance is 300 W; FIG. 11 is an enlarged diagram showing simulation results of the first embodiment when heat generation disturbance is 450 W; FIG. 11 is an enlarged view showing simulation results of the second embodiment when heat generation disturbance is 450 W;

Embodiments will be described below with reference to the accompanying drawings.

<First Embodiment>
First, the first embodiment will be described.
FIG. 1 is a perspective view showing a schematic configuration of an inspection apparatus according to the first embodiment, and FIG. 2 is a front view showing a cross section of a part of the inspection apparatus of FIG.

As shown in FIGS. 1 and 2, an inspection apparatus 1 inspects electrical characteristics of each of a plurality of electronic devices formed on a wafer W serving as a substrate to be inspected. , a loader 3 and a tester 4 .

The inspection unit 2 has a hollow housing 11 , and has a stage 10 in the housing 11 to which a wafer W to be inspected is fixed by suction. Further, the stage 10 is configured to be movable in horizontal and vertical directions by a moving mechanism (not shown). A temperature control device 20 is provided below the stage 10 to control the temperature of the stage. Temperature control device 20 will be described in detail later.

A probe card 12 is arranged above the stage 10 in the inspection section 2 so as to face the stage 10 . The probe card 12 has a plurality of probes 12a as contacts. Also, the probe card 12 is connected to the tester 4 via an interface 13 . When each probe 12a contacts the electrode of each electronic device on the wafer W, each probe 12a supplies power to the electronic device from the tester 4 via the interface 13, or receives a signal from the electronic device via the interface 13. to the tester 4.

The loader 3 has a housing 14 in which a FOUP (not shown), which is a transfer container containing wafers W, is arranged. The loader 3 also has a transfer mechanism (not shown), and the transfer device takes out the wafer W accommodated in the FOUP and transfers it to the stage 10 of the inspection section 2 . In addition, the wafer W on the stage 10 whose electrical characteristics have been inspected is transferred by the transfer device and housed in the FOUP.

In the housing 14 of the loader 3, there are provided a control unit 15 for performing various controls such as temperature control of the electronic device to be inspected, and a potential difference measuring unit for measuring the potential difference in the potential difference generating circuit (not shown) in each electronic device. 16 are provided. A potential difference generating circuit is, for example, a diode, a transistor or a resistor. The potential difference measurement unit 16 is connected to the interface 13, acquires the potential difference between the two probes 12a in contact with the two electrodes corresponding to the potential difference generation circuit, and transmits the acquired potential difference to the control unit 15. A connection structure of wiring from each probe 12a and the potential difference measurement unit 16 in the interface 13 will be described later.

The control unit 15 has a temperature controller 30 included in the temperature control device 20, and the temperature controller 30 controls a heating mechanism and a cooling mechanism, which will be described later. Note that the control section 15 and the potential difference measurement unit 16 may be provided inside the housing 11 of the inspection section 2 , and the potential difference measurement unit 16 may be provided in the probe card 12 .

The housing 11 of the inspection unit 2 is provided with a user interface unit 18 that constitutes a part of the control unit 15 . The user interface unit 18 is for displaying information for the user and allowing the user to input instructions, and includes, for example, an input unit such as a touch panel or keyboard and a display unit such as a liquid crystal display.

The tester 4 has a test board (not shown) that reproduces part of the circuit configuration of the motherboard on which the electronic device is mounted. The test board is connected to a tester computer 17 that determines whether the electronic device is good or bad based on signals from the electronic device. The tester 4 can reproduce circuit configurations of multiple types of motherboards by replacing the test board.

The probe card 12, interface 13, and tester 4 constitute an inspection mechanism.

When testing the electrical characteristics of an electronic device, the tester computer 17 sends data to the test board connected to the electronic device via each probe 12a. Then, the tester computer 17 determines whether or not the transmitted data is correctly processed by the test board based on the electrical signal from the test board.

As shown in FIG. 3, wafers W serving as substrates to be inspected are formed on the surface of a substantially disk-shaped silicon substrate at predetermined intervals by etching and wiring. It has a plurality of electronic devices D. An electrode E is formed on the surface of the electronic device D, and the electrode E is electrically connected to a circuit element inside the electronic device D. By applying a voltage to the electrode E, a current can flow to the circuit element inside each electronic device D. FIG.

Next, configurations of the stage 10 and the temperature control device 20 will be described with reference to FIG. FIG. 4 is a sectional view schematically showing the upper structure of the stage 10 and the temperature control device 20. As shown in FIG.

As shown in FIG. 4 , the stage 10 has a bottomed member 32 and a lid member 31 . The lid member 31 is attached on the bottomed member 32 via a seal ring 33 . The wafer W is held by suction on the lid member 31 .

The lid member 31 is formed in a disc shape and is made of SiC, for example. SiC has high thermal conductivity and Young's modulus. Further, the absorption efficiency of the light from the LED 41 of the heating mechanism 40 to be described later is also high, and the lid member 31 can be efficiently heated by the light from the heating mechanism 40 . In addition, SiC can be formed by sintering after molding into a green sheet, and the amount of processing can be reduced.

A suction hole (not shown) for sucking the wafer W is formed in the upper surface of the lid member 31 . A plurality of temperature sensors 31a are embedded in the lid member 31 at positions separated from each other in plan view.

The bottomed member 32 is formed in a disc shape having substantially the same diameter as the lid member 31, and is made of a material transparent to the wavelength of light emitted from the LED described later. A groove for flowing a coolant is formed in the upper portion of the bottomed member 32, and the groove is covered with the cover member 31 to form a coolant channel 32a. That is, the stage 10 has a coolant channel 32a inside.

The temperature control device 20 has a heating mechanism 40 , a cooling mechanism 50 and a temperature controller 30 . The temperature control device 20 controls the temperature of the electronic device D to be inspected formed on the wafer W on the stage 10 by heating by the heating mechanism 40 and cooling by the cooling mechanism 50 so as to be constant at a target temperature.

The heating mechanism 40 is configured as a light irradiation mechanism, and heats the lid member 31 of the stage 10 by irradiating the lid member 31 with light, thereby heating the wafer W and forming the electronic device D formed on the wafer W. to heat.

The heating mechanism 40 is arranged to face the surface of the stage 10 opposite to the wafer W mounting surface, that is, the lower surface of the bottomed member 32 . The heating mechanism 40 has a plurality of LEDs 41 that irradiate the wafer W with light as heat sources. Specifically, the heating mechanism 40 has a configuration in which a plurality of LED units 43 each having a plurality of LEDs 41 unitized are mounted on the surface of the base 42 . The LED units 43 in the heating mechanism 40 are, for example, as shown in FIG. It has a non-square unit 43b. Approximately the entire surface of the base 42 is covered by the units 43a and 43b, and the LEDs 41 of the LED unit 43 can irradiate at least the entire portion of the lid member 31 on which the wafer W is mounted.

Each LED 41 emits near-infrared light, for example. Light emitted from the LED 41 (hereinafter also referred to as “LED light”) is transmitted through the bottomed member 32 of the stage 10 made of a light transmitting member. The coolant flowing through the coolant passage 32 a is made of a material that transmits the light from the LED 41 , and the light transmitted through the bottomed member 32 passes through the coolant flowing through the coolant flow channel 32 a and enters the cover member 31 . When the light from the LED 41 is near-infrared light, polycarbonate, quartz, polyvinyl chloride, acrylic resin, or glass can be used as the light-transmitting member forming the bottomed member 32 . These materials are easy to process and mold.

In the heating mechanism 40 , the LED light incident on the lid member 31 on which the wafer W of the stage 10 is placed is controlled by each LED unit 43 . Therefore, the heating mechanism 40 can irradiate only an arbitrary portion of the lid member 31 with LED light, and can vary the intensity of the irradiated light between an arbitrary portion and other portions.

The cooling mechanism 50 has a chiller unit 51 , a refrigerant pipe 52 , a variable flow valve 53 and a high speed valve 54 . The chiller unit 51 stores refrigerant and controls the temperature of the refrigerant to a predetermined temperature. As the coolant, for example, water, which is a liquid through which the light emitted from the LED 41 can pass, is used. The refrigerant pipe 52 is connected to the supply port 32 b and the discharge port 32 c provided on the side portion of the bottomed member 32 and to the chiller unit 51 . The refrigerant in the chiller unit 51 is circulated and supplied to the refrigerant flow path 32 a through the refrigerant pipe 52 by a pump (not shown) provided in the refrigerant pipe 52 . The variable flow valve 53 is provided on the downstream side of the chiller unit 51 in the refrigerant pipe 52 , and the high-speed valve 54 is provided on the bypass pipe 52 a that bypasses the variable flow valve 53 on the downstream side of the chiller unit 51 . The variable flow rate valve 53 can set the flow rate, and supplies the refrigerant at a constant amount of the set flow rate. The high-speed valve 54 is opened/closed (on/off) at high speed based on a nonlinear gain term during sliding control, which will be described later, so that the refrigerant flowing through the bypass pipe 52a can be supplied/stopped at high speed.

Based on the measurement result of the temperature of the electronic device D, the temperature controller 30 controls the temperature of the stage by the heating mechanism 40 and the cooling mechanism 50 so that the temperature of the electronic device D reaches a predetermined temperature.

The temperature of the electronic device D is measured by the temperature measuring circuit 60 . FIG. 6 is a diagram schematically showing the configuration of a temperature measurement circuit 60 that measures the temperature of the electronic device D. As shown in FIG.

As shown in FIG. 6, each probe 12a is connected to the tester 4 by a plurality of wirings 61 arranged on the interface 13. FIG. A relay 62 is provided for each of the two wirings 61 connecting the tester 4 and the two probes 12a contacting the two electrodes E of the potential difference generating circuit (for example, diode) in the electronic device D. The relay 62 can also be connected to the wiring 63 of the potential difference measuring unit 16 .

That is, each relay 62 can switch and transmit the potential of each electrode E to either the tester 4 or the potential difference measuring unit 16 . For example, when inspecting the electrical characteristics of the electronic device D, the potential of each electrode E is transmitted to the potential difference measurement unit 16 at a predetermined timing after the mounting voltage is applied to each electrode E. It is known that the potential difference generated when a predetermined current is passed through the potential difference generating circuit varies depending on the temperature. Therefore, the temperature of the electronic device D can be measured in real time during testing based on the potential difference of the potential difference generating circuit of the electronic device D, that is, the potential difference between the two electrodes E (probes 12a) of the potential difference generating circuit.

That is, the temperature measuring circuit 60 includes a potential difference generating circuit in the electronic device D, two probes 12a in contact with the two electrodes thereof, two wirings 61 connected thereto, a relay 62, a wiring 63, and a potential difference measuring unit 16. consists of

Note that the method of measuring the temperature of the electronic device D is not limited to the one described above, and other methods may be used.

Based on the temperature measurement result of the electronic device D as described above, the temperature controller 30 performs a sliding mode control using the power (current value output) to be input to the LED 41 as a heating source as a manipulated variable, and a high-speed valve as a cooling source. The temperature is controlled by the cooling mode control using the power (that is, the open/close signal of the high-speed valve) as the manipulated variable.

Sliding mode control is a control method that switches control above and below a switching hyperplane so as to constrain the state to a preset switching hyperplane (switching plane) in the state space. If the initial state of the controlled object is outside the switching hyperplane, the state of the controlled object is made to reach and constrain the switching hyperplane in a finite time (arrival mode). When the state of the controlled object reaches the switching hyperplane, the state is made to converge to the target value while sliding on the switching hyperplane (sliding mode). A control input u of the sliding mode control is the sum of a linear term (linear control manipulated variable) u _l and a nonlinear term (nonlinear control manipulated variable) u _nl , and can be expressed by the following equation.
u=−(SB) ⁻¹ SAx−K(SB) ⁻¹ ·sgn(σ)
=-(SB) ^-1 {SAx+K·sgn(σ)}
σ=Sx
SAx is a linear term and K·sgn(σ) is a nonlinear term. A and B are matrices of state equations, and S and K are control parameters. The function sgn represents a discontinuous function, and sgn(σ) is the sliding mode switching function. The switching hyperplane can be designed in the framework of linear control, and in the sliding mode, the switching hyperplane moves back and forth between regions II and I shown in FIG. go. That is, in the sliding mode, the linear term (linear control manipulated variable) sets the state of the control system so that the control error is minimized on the switching hyperplane, and the nonlinear term (nonlinear control manipulated variable) is the modeling error and uncertain disturbances. forces the state of the control system towards the switching hyperplane.

FIG. 8 is a diagram showing control blocks of the temperature controller 30. As shown in FIG. The temperature controller 30 has a sliding mode controller 71 , a cooling mode controller 72 , a switching controller 73 and a plant model 74 .

The sliding mode controller 71 outputs power (output as a current value) input to the LED 41 of the heating mechanism 40 as a manipulated variable to perform temperature control. In the sliding mode controller 71, as shown in FIG. 9, the temperature detection signal x is input, and the control input u is changed by a linear term (linear gain term) and a nonlinear term (nonlinear gain term) generated by the nonlinear input section 75. It is formed. As shown in FIG. 10, the nonlinear input unit 75 generates a nonlinear input (nonlinear term): u _nl from the switching function σ, SWgain: k, and SWita: η. u _nl is represented by the following formula.
u _nl =−k·σ/(|σ|+η)
η is a chattering suppression term. Non-linear input (non-linear term): Since the switching frequency of u _nl is infinite, the state quantity chatters (high-frequency vibration) in the vicinity of the switching hyperplane. Therefore, η is used to suppress chattering and smooth the input.

FIG. 11 is a block diagram showing the inside of the cooling mode controller 72 and switching controller 73. As shown in FIG.
The cooling mode controller 72 performs cooling control using the power (opening/closing signal of the high speed valve 54) applied to the high speed valve 54 as a cooling source as an operation amount. Thereby, the amount of coolant supplied to the coolant channel 32a of the stage 10 is controlled, and the temperature of the electronic device D is controlled. The output of the cooling mode controller 72 is calculated by an endothermic model based on the refrigerant flow rate and endothermic coefficient. Although the endothermic coefficient is indicated as −0.4 in FIG. 11, this is only an example, and the value varies depending on the electronic device D and the like.

The switching controller 73 uses the value of the nonlinear term u _nl of the sliding mode controller as a switching signal. That is, the switching controller 73 uses the output (control input) of the sliding mode controller 71 as it is, or does not use the output of the sliding controller 71 and switches the output of the cooling mode controller 72 to the second mode depending on the value of the nonlinear term u _nl . Decide whether to use it as an manipulated variable.

Using the output (control input) of the sliding mode controller 71 as it is means outputting the output of the sliding mode controller 71 as the first manipulated variable to the LED 41 that is the heat source.

Using the output of the cooling mode controller 72 as the second manipulated variable means using the output of the high-speed valve, which is the cooling source of the cooling mode controller 72, as the second manipulated variable.

Specifically, when the value of the nonlinear term u _nl is positive (one side of the switching hyperplane; region I in FIG. 7), the switching controller 73 directly uses the output of the sliding mode controller 71 as the first manipulated variable. Output to the LED 41 . When the value of the nonlinear term u _nl is negative (the other side of the switching hyperplane; region II in FIG. 7), the output of the high-speed valve (high-speed valve open/close signal) that is the cooling source of the cooling mode controller 72 is 2 is used as the manipulated variable. The opening and closing time of the high-speed valve is as fast as 0.1 sec or less, and the high-speed valve 54 can be opened and closed following high-speed switching by the nonlinear term u _nl , and can perform temperature control with high controllability.

The plant model 74 is a physical model of the electronic device D (stage 10) that is subject to temperature control, as shown in FIG. A signal output from the switching controller 73 is input to the plant model 74, and a control signal is obtained through necessary calculations in the plant model 74. FIG.

The temperature control of the electronic device D is performed by the temperature controller 30 while the variable flow rate valve 53 of the cooling mechanism 50 causes the coolant to flow through the coolant channel 32a at a constant flow rate to absorb heat. That is, the temperature controller 30 performs sliding mode control using the power input to the LED 41 as the heating source as an operation amount, and cooling using the power input to the high-speed valve 54 as the cooling source (high-speed valve opening/closing signal) as an operation amount. Temperature control is performed by mode control. At this time, depending on the value of the nonlinear term u _nl , the switching controller 73 performs sliding mode control using the nonlinear term _unl as it is, or performs cooling mode control using the nonlinear term _unl as an open/close signal for the high-speed valve 54 . is determined. When the value of the nonlinear term u _nl of the sliding mode control is positive, the temperature control is performed by the sliding mode control using the power input to the LED 41 as the manipulated variable. When the value of the nonlinear term u _nl of the sliding mode control becomes negative, the nonlinear term u _nl is output as an opening/closing signal for the high speed valve 54, and the sliding mode control of the LED 41 is switched to the cooling mode control. At this time, the output of the sliding mode controller 71 is not used for temperature control. By using cooling mode control, the electronic device D can be cooled more than if the LED 41 were turned off. This ensures the temperature controllability of the electronic device D when there is a very large heat generation disturbance.

The control unit 15 comprises a computer, and in addition to the temperature controller 30, has a main control unit having a plurality of control function units for controlling each component of the inspection apparatus 1. The main control unit controls each component of the inspection apparatus. control the operation of the Also, the control unit has an input device, an output device, a display device, and a storage device. Control of each component by the main controller is executed by a processing recipe, which is a control program stored in a storage medium (hard disk, optical disk, semiconductor memory, etc.) built into the storage device.

Next, an example of inspection processing for the wafer W using the inspection apparatus 1 will be described.
First, the wafer W is taken out from the FOUP of the loader 3 by the transfer device, transferred to the stage 10, and placed thereon. Next, the stage 10 is moved to a predetermined position.

Then, all the LEDs 41 of the heating mechanism 40 are turned on, and based on the information acquired from the temperature sensor 31a of the lid member 31, the light output from the LEDs 41 and the , the flow rate of the coolant flowing through the coolant channel 32 a in the stage 10 is adjusted by the variable flow valve 53 .

In this state, the potential difference measurement unit 16 acquires the potential difference of the aforementioned potential difference generation circuit in the electronic device D to be inspected. Then, assuming that the temperature of the lid member 31 made uniform in the plane substantially coincides with the temperature of the electronic device D to be inspected, the potential difference is calibrated, and the temperature characteristic information of the potential difference is corrected.

Thereafter, the stage 10 is moved to bring the probes 12a provided above the stage 10 into contact with the electrodes E of the electronic devices D on the wafer W to be inspected. A signal for inspection is input to the probe 12a. Thereby, the inspection of the electronic device D is started.

During the inspection, the temperature of the electronic device D to be inspected is measured based on the information on the potential difference generated in the potential difference generating circuit of the electronic device D to be inspected. temperature control is performed.

At this time, temperature control is performed by the temperature controller 30 while the variable flow rate valve 53 of the cooling mechanism 50 allows the coolant to flow through the coolant channel 32a at a constant flow rate to absorb heat. That is, the temperature controller 30 controls a sliding mode control in which the power input to the LED 41, which is the heating source, is used as an operation amount, and a cooling mode in which the power input to the high-speed valve 54, which is the cooling source (high-speed valve opening/closing signal), is an operation amount. Temperature control by control. At this time, the switching controller 73 uses the output (control input) of the sliding mode controller 71 as it is, or uses the nonlinear term u _nl as the opening/closing signal for the high-speed valve 54, as described above, depending on the value of the nonlinear term u _nl . Decide whether to control the cooling mode. Specifically, when the value of the nonlinear term u _nl of the sliding mode control is positive, the output of the sliding mode controller 71 is directly output to the LED 41 as the first manipulated variable. On the other hand, when the nonlinear term u _nl is negative, the nonlinear term u _nl is used as an opening/closing signal for the high speed valve 54 and is output to the high speed valve as a second manipulated variable.

In the inspection apparatus of Patent Document 1, when inspecting the electrical characteristics of an electronic device, in order to reproduce the mounting environment of the electronic device, the temperature of the mounting table is controlled by the coolant flow path and the heater in the mounting table. ing.

On the other hand, in recent years, electronic devices have advanced in speed and miniaturization, the degree of integration has increased, and the amount of heat generated during operation has increased significantly. There is a risk of malfunction of the electronic device. However, Japanese Patent Application Laid-Open No. 2002-200002 does not disclose a method for eliminating such heat generation disturbance.

Therefore, in the present embodiment, the variable flow rate valve 53 of the cooling mechanism 50 is used to flow the coolant through the coolant supply path 32a of the stage 10 at a constant flow rate to ensure heat absorption. The temperature of the electronic device D is controlled by using the power (current value) applied to the LED 41 of .

However, with only the sliding mode control in which the coolant flow rate is constant and the power input to the LED 41 is the manipulated variable, heat absorption becomes insufficient even if the LED 41 is turned off when the heat generation disturbance becomes extremely large. For this reason, there are cases where the response of disturbance control becomes slow, and where sufficient temperature control cannot be performed. It is also conceivable to increase the flow rate of the coolant to improve the heat absorption, but in this case, the output of the LED 41 is insufficient and the target temperature cannot be reached. In some cases, it is possible to suppress the temperature rise of the electronic device by using an LED with a large maximum output or increasing the density of the LED while increasing the flow rate of the coolant. It increases and is not realistic.

Therefore, in the present embodiment, the variable flow valve 53 of the cooling mechanism 50 allows the refrigerant to flow through the refrigerant flow path 32a at a constant flow rate to absorb heat, while the sliding mode control in which the power input to the LED 41 is the manipulated variable, and the high-speed valve 54 The switching controller 73 performs switching between the cooling mode control using the power (opening/closing signal of the high-speed valve) as the manipulated variable according to the value of the nonlinear term u _nl . That is, when the value of the nonlinear term u _nl of the sliding mode control is positive, the influence of the heat disturbance is small, so the output of the sliding mode controller 71 is applied as it is to the LED 41, which is the heat source, as the first manipulated variable. On the other hand, when the value of the nonlinear term u _nl is negative, cooling mode control is performed using the power (opening/closing signal of the high speed valve) applied to the high speed valve 54 as the cooling source as the second manipulated variable. That is, when the heat disturbance of the electronic device D is large during sliding mode control and the nonlinear term u _nl of the sliding mode control becomes negative, the switching controller 73 switches to the cooling mode control. Thereby, the stage 10 can be cooled more than when the LED 41 is turned off, and the cooling capacity is enhanced. Therefore, even if there is a very large heat generation disturbance, the temperature of the electronic device D can be sufficiently cooled, and the temperature of the electronic device D can be controlled with good controllability. It is desirable that the position of the high-speed valve 54 at this time be as close to the stage 10 as possible from the viewpoint of minimizing dead time.

Further, since the heating mechanism 40 is provided with a plurality of LED units 43 mounted with a plurality of LEDs 41 so as to correspond to each of the plurality of electronic devices D, the electronic devices D can be individually heated. can be done. Therefore, only the electronic device D under inspection can be heated, and heat disturbance to other electronic devices D can be suppressed.

Furthermore, since the cooling mode control is performed using the high-speed valve 54, the high-speed valve 54 can be opened and closed according to the positive/negative fluctuation of the nonlinear term u _nl used as the switching signal, and the cooling control can be performed with high accuracy. can be done.

In addition, since water can be used as a refrigerant, it is not necessary to use a fluorocarbon refrigerant, and the heat absorption is better than when a chlorofluorocarbon refrigerant is used, and heat absorption can be accelerated.

Incidentally, the inspection of electronic devices may be performed on a plurality of devices at once, or may be performed on all electronic devices at once like batch contact probing employed in DRAMs and the like. In either case, the temperature of the electronic device to be inspected is controlled by the sliding mode control using the power of the LED 41 as the manipulated variable as described above, and the cooling mode control by opening and closing the high-speed valve. temperature control can be performed.

<Second embodiment>
Next, a second embodiment will be described.
The basic configuration of the inspection apparatus of the second embodiment is the same as that of the inspection apparatus 1 of the first embodiment, but is included in the temperature control apparatus 20 of the first embodiment as shown in FIG. 13 described later. The only difference from the inspection apparatus 1 of the first embodiment is that a temperature controller 30' having a different control method is installed instead of the temperature controller 30. FIG.

As with the temperature controller 30 of the first embodiment, the temperature controller 30' of the present embodiment also operates the power (current value output) to be applied to the LED 41, which is the heat source, based on the temperature measurement result of the electronic device D. Control is performed based on sliding mode control. Further, in the temperature controller 30', in addition to the sliding mode control, the temperature controller 30' performs the cooling mode control using the power input to the high-speed valve (that is, the open/close signal of the high-speed valve) as the manipulated variable, as in the temperature controller 30 of the first embodiment. . However, the temperature controller 30' of this embodiment is different from the temperature controller 30 in that the control signal is also sent to the LED 41, which is the heating source, in the cooling mode.

The temperature controller 30' will be described in detail below.
FIG. 13 is a diagram showing control blocks of the temperature controller 30'. The temperature controller 30 ′ has a sliding mode controller 71 , a cooling mode controller 72 , an adder 77 , a switching controller 73 ′ and a plant model 74 . The basic configurations of the sliding mode controller 71, the cooling mode controller 72, and the plant model 74 are the same as those of the temperature controller 30 of the first embodiment.

FIG. 14 is a block diagram showing the configurations of the cooling mode controller 72, the adder 77 and the switching controller 73' and the transmission and reception of these signals.

As described above, the cooling mode controller 72 performs cooling control using the power (opening/closing signal of the high speed valve 54) applied to the high speed valve 54, which is the cooling source, as the manipulated variable. Thereby, the amount of coolant supplied to the coolant channel 32a of the stage 10 is controlled, and the temperature of the electronic device D is controlled. The output of the cooling mode controller 72 is calculated by an endothermic model based on the refrigerant flow rate and endothermic coefficient. Although the endothermic coefficient is indicated as −20 in FIG. 14, this is only an example, and the value varies depending on the electronic device D and the like.

The switching controller 73', like the switching controller 73 of the first embodiment, uses the value of the nonlinear term u _nl of the sliding mode controller as a switching signal. Then, the switching controller 73' determines whether to use the output of the sliding mode controller 71 as it is or to use the second manipulated variable, depending on the value of the nonlinear term u _nl . The switching controller 73' uses the sum of the sliding mode output and the output of the cooling mode controller 72 in the adder 77 as the second manipulated variable. That is, the second manipulated variable is the sum of the output from the sliding mode controller 71 to the LED 41 which is the heating source and the output of the high speed valve which is the cooling source of the cooling mode controller 72 .

Using the output (control input) of the sliding mode controller 71 as it is means outputting the output of the sliding mode controller 71 as the first manipulated variable to the LED 41 that is the heat source.

Specifically, when the value of the nonlinear term u _nl is positive (on one side of the switching hyperplane; region I in FIG. 7), the switching controller 73 ′ directly converts the output of the sliding mode controller 71 into the first manipulated variable. is output to the LED 41 as . When the value of the nonlinear term u _nl is negative (the other side of the switching hyperplane; region II in FIG. 7), the output of the sliding mode controller 71 and the output of the high-speed valve, which is the cooling source of the cooling mode controller 72 ( A high-speed valve open/close signal) is used as the second manipulated variable.

As described above, the cooling mode controller 72 opens and closes the high-speed valve 54, which operates at a high speed of 0.1 sec or less, following the high-speed switching by the nonlinear term u _nl . As a result, the electronic device D can be cooled more than when the LED 41 is turned off, and the temperature controllability of the electronic device D can be ensured in the event of a very large heat generation disturbance. In addition, as the second manipulated variable, not only the output of the high-speed valve of the cooling mode controller 72 but also the output of the sliding mode controller 71 is added, thereby easing the transient response of rapid cooling and achieving good controllability. Obtainable.

Also in this embodiment, the inspection of the electronic device D is started as in the first embodiment. During the inspection, the temperature of the electronic device D to be inspected is measured based on information on the potential difference generated in the potential difference generating circuit of the electronic device D to be inspected. Temperature control of device D is performed.

At this time, the temperature is controlled by the temperature controller 30' while the variable flow rate valve 53 of the cooling mechanism 50 allows the coolant to flow through the coolant channel 32a at a constant flow rate to absorb heat. In the temperature controller 30', the switching controller 73' uses the output of the sliding mode controller 71 as it is or converts the sliding mode output and the output of the cooling mode controller 72 into a second manipulated variable depending on the value of the nonlinear term u _nl . Decide whether to use Specifically, when the value of the nonlinear term u _nl of the sliding mode control is positive, the output of the sliding mode controller 71 is directly output to the LED 41 as the first manipulated variable. On the other hand, when the nonlinear term u _nl is negative, the sum of the output of the sliding mode controller 71 and the output of the high-speed valve serving as the cooling source of the cooling mode controller 72 is output as the second manipulated variable.

In the first embodiment, the cooling mode controller 72 opens and closes the high-speed valve 54, which operates at a high speed of 0.1 sec or less, following the high-speed switching by the nonlinear term u _nl . As a result, the electronic device D can be cooled more than when the LED 41 is turned off, and the temperature controllability of the electronic device D can be ensured in the event of a very large heat generation disturbance.

However, in the first embodiment, although the controllability is good, when the nonlinear term u _nl is negative, only the high-speed valve 54 operates, which may result in rapid cooling transient response. In other words, it is necessary to increase the output of the LED 41 in order to compensate for the temperature drop of the electronic device D when the high-speed valve 54 is opened by the switching controller 73'. timing) will also be faster. Therefore, during control by the switching controller 73', the amplitude of the current value tends to be large and the frequency of opening the high-speed valve 54 tends to increase.

In contrast, in this embodiment, not only the output of the high-speed valve of the cooling mode controller 72 but also the output of the sliding mode controller 71 is added as the second manipulated variable when the nonlinear term u _nl is negative. In this way, the control signal is also sent to the LED 41 at the same time while the high-speed valve 54 is operating, so the transient response of rapid cooling can be mitigated. Therefore, in addition to the basic effects of the first embodiment, the amplitude of the current value can be reduced and the frequency of opening the high-speed valve 54 can be reduced, enabling smoother temperature control with smaller amplitude. It also has the effect of

In addition, in the second embodiment, since the basic configuration of the inspection apparatus is the same as that in the first embodiment, other effects obtained in the first embodiment can also be obtained in the second embodiment. can be done.

<Simulation result>
Next, simulation results will be described.
Here, the temperature controllability was simulated when heat generation disturbances of 150 W, 300 W, and 450 W were applied to an electronic device (chip) having a size of 30 mm×40 mm formed on a wafer.

FIGS. 15 to 17 are diagrams showing the results of simulating the temperature control of the chip by sliding mode control using the power input to the LED as the manipulated variable while supplying a coolant at a constant flow rate.

As shown in FIG. 15, in the case of sliding mode control, good controllability can be maintained at a heat generation disturbance of 150 W, but as shown in FIGS. was observed, and it was confirmed that the temperature could not be controlled.

18 to 20 are simulations of the first embodiment using both sliding mode control with the power input to the LED as the manipulated variable and cooling mode control by high-speed valve opening and closing performed when the nonlinear term u _nl is negative. FIG. 10 is a diagram showing the results of the experiment.

As shown in these figures, according to the first embodiment, which uses both the sliding mode control and the cooling mode control by opening and closing the high-speed valve, good temperature control can be achieved in any case where a heat generation disturbance of 150 W to 450 W is applied. was confirmed to be possible.

FIGS. 21-23 show simulation results of a second embodiment using both sliding mode control and control with a sliding mode controller output and a cooling mode controller output performed when the nonlinear term u _nl is negative. It is a diagram.

As shown in these figures, according to the second embodiment, in which both the sliding mode control and the control in which the sliding mode controller output and the cooling mode controller output are added, good heat generation disturbance of 150 W to 450 W can be obtained. It was confirmed that the temperature could be controlled appropriately. Also, it can be seen that the amplitude of the supplied current in the case where heat generation disturbance occurs is smaller in the second embodiment than in the first embodiment.

24 and 25 are enlarged diagrams showing the simulation results of the first embodiment and the second embodiment when the heat generation disturbance is 150 W, respectively. From these figures, it can be seen that the second embodiment has a smaller amplitude of current output and a smaller control amplitude than the first embodiment. Also, it can be seen that the overshoot and undershoot of the temperature to be controlled at the timing when the heat generation disturbance abruptly changes are smaller in the second embodiment.

26 and 27 are enlarged diagrams showing simulation results of the first embodiment and the second embodiment when the heat generation disturbance is 300 W, respectively. 28 and 29 are enlarged diagrams showing simulation results of the first embodiment and the second embodiment when the heat generation disturbance is 450 W, respectively. As is clear from these figures, even when the disturbance is increased to 300 W and 450 W, the amplitude of the current output in the second embodiment is smaller than that in the first embodiment, as in the case of the disturbance of 150 W. , the control amplitude is small. Also, it can be seen that the overshoot and undershoot of the temperature to be controlled at the timing when the heat generation disturbance abruptly changes are smaller in the second embodiment.

<Other applications>
Although the embodiments have been described above, the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various ways without departing from the scope and spirit of the appended claims.

For example, in the above-described embodiment, the LED is used as the heat source, but the heat source is not limited to the LED, and may be another heat source such as a resistance heater. In the above embodiment, an electronic device (chip) on a wafer is taken as an example of a temperature controlled object, but the temperature controlled object may be a stage and is not limited to an electronic device (chip). Moreover, the application of the temperature control device is not limited to the inspection device.

Tester 10; Stage 12; Probe card 12a; Probe 13; Interface 15; Control unit 20; Flow path 40; heating mechanism 41; LED
Refrigerant piping 53; Variable flow valve 54; High speed valve 60; Circuit for temperature measurement 71; Sliding mode controller 72; Electronic device (temperature measurement target)
W; wafer

Claims (17)

A temperature control device for controlling the temperature of a temperature controlled object,
a heating mechanism having a heating source for heating the temperature controlled object;
a cooling mechanism having a cooling source for cooling the temperature controlled object;
a temperature controller that controls the heating source and the cooling source;
with
The temperature controller
A temperature measurement value of the temperature control object is a control object,
a sliding mode controller whose manipulated variable is the power supplied to the heating source;
a cooling mode controller whose manipulated variable is the power input to the cooling source;
Of the linear term and the nonlinear term that are outputs of the sliding mode controller, depending on the value of the nonlinear term, either the output of the sliding mode controller is directly output to the heating source as a first manipulated variable, or the sliding mode controller is output to the heating source. a switching controller that determines whether to output the output of the cooling mode controller as a second manipulated variable to the cooling source without using the output of the controller;
has
The switching controller uses only the output of the sliding mode controller when the nonlinear term is in the region on one side of the switching hyperplane in sliding mode control, and when it is in the region on the other side of the switching hyperplane, , a temperature controller that switches to use the output of said cooling mode controller . A temperature control device for controlling the temperature of a temperature controlled object,
a heating mechanism having a heating source for heating the temperature controlled object;
a cooling mechanism having a cooling source for cooling the temperature controlled object;
a temperature controller that controls the heating source and the cooling source;
with
The temperature controller
A temperature measurement value of the temperature control object is a control object,
a sliding mode controller whose manipulated variable is the power supplied to the heating source;
a cooling mode controller whose manipulated variable is the power input to the cooling source;
Of the linear term and the nonlinear term that are outputs of the sliding mode controller, depending on the value of the nonlinear term, either the output of the sliding mode controller is directly output to the heating source as a first manipulated variable, or the sliding mode controller is output to the heating source. a switching controller that determines whether to output the sum of the output of the controller and the output of the cooling mode controller as a second manipulated variable to the heating source and the cooling source ;
has
The switching controller uses only the output of the sliding mode controller when the nonlinear term is in the region on one side of the switching hyperplane in sliding mode control, and when it is in the region on the other side of the switching hyperplane, , a temperature controller that switches to use the output of said cooling mode controller . 3. The region according to claim 1 , wherein the one-side region is a region in which the value of the nonlinear term is positive, and the region on the other side is a region in which the value of the nonlinear term is negative. temperature controller. 4. The temperature control device according to any one of claims 1 to 3 , wherein said heat source is an LED, and said first manipulated variable is a current value supplied to said LED. 2. The cooling mechanism cools the temperature controlled object with a coolant, the cooling source is a valve that opens and closes a coolant flow path, and the output of the cooling mode controller is an open/close signal to the valve . 5. A temperature control device according to any one of claims 1 to 4 . 6. The temperature control device according to claim 5, wherein said cooling mechanism absorbs heat from said temperature controlled object by supplying said coolant at a constant flow rate in addition to the power supplied to said cooling source by said cooling mode controller. The temperature control apparatus according to any one of claims 1 to 6 , wherein the temperature control object is an electronic device provided on a substrate. A temperature control method for temperature control of a temperature control object,
A temperature measurement value of the temperature control object is a control object,
a step of performing sliding mode control using power input to a heating source for heating the temperature controlled object as a manipulated variable;
a step of performing cooling mode control using power input to a cooling source for cooling the temperature controlled object as a manipulated variable;
Of the linear term and the nonlinear term that are the output in the sliding mode control, depending on the value of the nonlinear term, the output of the sliding mode control is directly output to the heating source as a first manipulated variable, or the sliding mode control determining whether to output the cooling mode control output as a second manipulated variable to the cooling source without using the control output;
has
In the determining step, the nonlinear term uses only the sliding mode control in a region on one side of the switching hyperplane in sliding mode control, and if it is in a region on the other side of the switching hyperplane, the cooling A temperature control method that switches to use the mode control output . A temperature control method for temperature control of a temperature control object,
A temperature measurement value of the temperature control object is a control object,
a step of performing sliding mode control using power input to a heating source for heating the temperature controlled object as a manipulated variable;
a step of using both the sliding mode control and a cooling mode control in which power input to a cooling source for cooling the temperature controlled object is used as a manipulated variable;
Of the linear term and the nonlinear term that are the output in the sliding mode control, depending on the value of the nonlinear term, the output of the sliding mode control is directly output to the heating source as a first manipulated variable, or the sliding mode control determining whether to output the sum of the control output and the cooling mode control output as a second manipulated variable to the heating source and the cooling source ;
has
In the determining step, the nonlinear term uses only the sliding mode control in a region on one side of the switching hyperplane in sliding mode control, and if it is in a region on the other side of the switching hyperplane, the cooling A temperature control method that switches to use the mode control output . 10. The region according to claim 8 , wherein the one side region is a region in which the value of the nonlinear term is positive, and the region on the other side is a region in which the value of the nonlinear term is negative. temperature control method. 11. The temperature control method according to any one of claims 8 to 10 , wherein said heat source is an LED, and said first manipulated variable is a current value supplied to said LED. 12. The cooling source according to any one of claims 8 to 11 , wherein the cooling source is a valve that opens and closes a flow path of a coolant that cools the temperature controlled object, and the manipulated variable of the cooling mode control is an open/close signal to the valve . 1. The temperature control method according to claim 1. 13. The temperature control method according to claim 12 , wherein the cooling medium is supplied at a constant flow rate to absorb heat from the object to be temperature controlled, independently of the operation amount for the cooling mode control. 14. The temperature control method according to any one of claims 8 to 13 , wherein said temperature control object is an electronic device provided on a substrate. a stage on which a substrate provided with an electronic device is placed;
an inspection mechanism that electrically contacts a probe to the electronic device provided on the substrate on the stage to inspect the electronic device;
a temperature measurement unit that measures the temperature of the electronic device;
a temperature control device that controls the temperature of the electronic device;
and
The temperature control device is
a heating mechanism having a heating source that heats the electronic device;
a cooling mechanism having a cooling source for cooling the electronic device;
a temperature controller that controls the heating source and the cooling source;
with
The temperature controller
Controlling the temperature measurement value of the electronic device,
a sliding mode controller whose manipulated variable is the power supplied to the heating source;
a cooling mode controller whose manipulated variable is the power input to the cooling source;
Of the linear term and the nonlinear term that are outputs of the sliding mode controller, depending on the value of the nonlinear term, either the output of the sliding mode controller is directly output to the heating source as a first manipulated variable, or the sliding mode controller is output to the heating source. a switching controller that determines whether to output the output of the cooling mode controller as a second manipulated variable to the cooling source without using the output of the controller;
has
The switching controller uses only the output of the sliding mode controller when the nonlinear term is in the region on one side of the switching hyperplane in sliding mode control, and when it is in the region on the other side of the switching hyperplane, , an inspection device that switches to use the output of said cooling mode controller . a stage on which a substrate provided with an electronic device is placed;
an inspection mechanism that electrically contacts a probe to the electronic device provided on the substrate on the stage to inspect the electronic device;
a temperature measurement unit that measures the temperature of the electronic device;
a temperature control device that controls the temperature of the electronic device;
and
The temperature control device is
a heating mechanism having a heating source that heats the electronic device;
a cooling mechanism having a cooling source for cooling the electronic device;
a temperature controller that controls the heating source and the cooling source;
with
The temperature controller
Controlling the temperature measurement value of the electronic device,
a sliding mode controller whose manipulated variable is the power supplied to the heating source;
a cooling mode controller whose manipulated variable is the power input to the cooling source;
Of the linear term and the nonlinear term that are outputs of the sliding mode controller, depending on the value of the nonlinear term, either the output of the sliding mode controller is directly output to the heating source as a first manipulated variable, or the sliding mode controller is output to the heating source. a switching controller that determines whether to output the sum of the output of the controller and the output of the cooling mode controller as a second manipulated variable to the heating source and the cooling source ;
has
The switching controller uses only the output of the sliding mode controller when the nonlinear term is in the region on one side of the switching hyperplane in sliding mode control, and when it is in the region on the other side of the switching hyperplane, , an inspection device that switches to use the output of said cooling mode controller . a stage on which a substrate provided with an electronic device is placed;
an inspection mechanism that electrically contacts a probe to the electronic device provided on the substrate on the stage to inspect the electronic device;
a temperature measurement unit that measures the temperature of the electronic device;
a temperature control device that controls the temperature of the electronic device;
and
The temperature control device is
a heating mechanism having a heating source that heats the electronic device;
a cooling mechanism having a cooling source for cooling the electronic device;
a temperature controller that controls the heating source and the cooling source;
with
The cooling mechanism is
a coolant source that supplies a coolant as the cooling source;
a first refrigerant pipe connected to the refrigerant source and the stage and supplying a constant amount of the refrigerant from the refrigerant source to the stage;
a second refrigerant pipe provided in parallel with the first refrigerant pipe for supplying the refrigerant from the refrigerant source to the stage;
a valve provided in the second refrigerant pipe for supplying/stopping the refrigerant to the stage;
An inspection device.

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